  United States Court of Appeals
      for the Federal Circuit
                ______________________

    BLACKBIRD TECH LLC, DBA BLACKBIRD
             TECHNOLOGIES,
              Plaintiff-Appellant

                           v.

  ELB ELECTRONICS, INC., ETI SOLID STATE
LIGHTING INC., FEIT ELECTRIC COMPANY INC.,
             Defendants-Appellees
            ______________________

                      2017-1703
                ______________________

    Appeal from the United States District Court for the
District of Delaware in Nos. 1:15-cv-00056-RGA, 1:15-cv-
00057-RGA, 1:15-cv-00058-RGA, 1:15-cv-00062-RGA,
Judge Richard G. Andrews.
                 ______________________

                Decided: July 16, 2018
                ______________________

    SEAN KEVIN THOMPSON, Blackbird Technologies,
Boston, MA argued for plaintiff-appellant. Represented
by WENDY VERLANDER; CHRISTOPHER FREEMAN, Chicago,
IL; STAMATIOS STAMOULIS, Stamoulis & Weinblatt LLC,
Wilmington, DE.

   JOHN HINTZ, Maynard, Cooper & Gale, PC, New York,
NY, argued for all defendants-appellees.
2                BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



   PHILIP A. ROVNER, Potter Anderson & Corroon, LLP,
Wilmington, DE, for defendant-appellee ETi Solid State
Lighting Inc. Also represented by JONATHAN A. CHOA,
ALAN R. SILVERSTEIN; DAVID PETER HOCHBERG, Walter
Haverfield LLP, Cleveland, OH.
                ______________________

    Before PROST, Chief Judge, MOORE and REYNA, Circuit
                          Judges.
     Opinion for the court filed by Circuit Judge MOORE.
      Dissenting opinion filed by Circuit Judge REYNA.
MOORE, Circuit Judge.
    Blackbird Tech LLC (“Blackbird”) appeals the U.S.
District Court for the District of Delaware’s entry of
judgment of noninfringement of claim 12 of U.S. Patent
No. 7,086,747 (“’747 patent”) based on its construction of
“attachment surface.” Because the court erred in constru-
ing “attachment surface,” we vacate and remand.
                       BACKGROUND
     Blackbird owns the ’747 patent, which is directed to
energy efficient lighting apparatuses. ’747 patent at
Abstract, 2:24–3:16. One embodiment, illustrated in
Figure 5 below, discloses retrofitting an existing light
fixture with a more energy efficient lighting apparatus.
Id. at 9:1–10:28.
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.              3



Id. at Fig. 5. This embodiment depicts a lighting appa-
ratus 500, which includes a housing 528 that is dimen-
sioned to be installed to an existing ballast cover 1 (not
shown). Id. at 9:12–16. The housing has an attachment
surface 530 and an illumination surface 532 at opposite
ends. Id. at 9:16–20. In “typical operation” the attach-
ment surface is secured to the ballast cover of the existing
light fixture through a fastening mechanism 534. Id. at
9:16–19, 9:36–51.
    Blackbird sued ELB Electronics, Inc., ETi Solid State
Lighting Inc., and Feit Electric Company, Inc. (collective-
ly, “Defendants”) for infringing claim 12 of the ’747 pa-
tent. It recites:
   12. An energy-efficient lighting apparatus for ret-
   rofit with an existing light fixture having a ballast
   cover, comprising:
       a housing having an attachment surface
       and an illumination surface;
       a plurality of illumination surface holes in
       the illumination surface;
       a circuit board comprising a plurality of
       light-emitting diodes, wherein the circuit
       board is positioned adjacent the housing
       so that the plurality of light-emitting di-
       odes protrude through the plurality of il-
       lumination     surface    holes   in   the
       illumination surface; and




   1    The specification explains that the ballast is an
electronic component that maintains a current through
the fluorescent lights to illuminate them. Id. at 5:1–14,
65–67. The ballast cover conceals the ballast and other
wiring. Id. at 5:2–4.
4              BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



       a fastening mechanism for securing the at-
       tachment surface of the lighting apparatus
       to the illumination surface, wherein the
       lighting apparatus is coupled to a wall
       switch and wherein the illumination of the
       light-emitting diodes is controllable based
       upon the position of the wall switch.
    The parties disputed the meaning of “attachment sur-
face,” specifically whether the attachment surface must be
secured to the ballast cover. Blackbird proposed constru-
ing “attachment surface” as “layer of the housing to which
the illumination surface is secured,” and Defendants
proposed “layer of the housing that is secured to the
ballast cover and to which the illumination surface is
secured.” J.A. 7. The district court construed “attach-
ment surface” as “layer of the housing that is secured to
the ballast cover.” J.A. 7–9.
    Following claim construction, Blackbird stipulated to
noninfringement, and the district court entered judgment
in favor of Defendants. Blackbird timely appeals. We
have jurisdiction under 28 U.S.C. § 1295(a)(1).
                       DISCUSSION
    We review claim construction based solely on intrinsic
evidence de novo. Poly-Am., L.P. v. API Indus., Inc., 839
F.3d 1131, 1135–36 (Fed. Cir. 2016). “The words of a
claim are generally given their ordinary and customary
meaning as understood by a person of ordinary skill in the
art when read in the context of the specification and
prosecution history.” Thorner v. Sony Comput. Entm’t
Am. LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012).
    We conclude that the district court erred in construing
“attachment surface” to be secured to the ballast cover.
By its plain language, claim 12 does not require the
attachment surface to be secured to the ballast cover.
Claim 12 expressly recites a fastening mechanism for
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.              5



securing the attachment surface to the illumination
surface. It does not refer to any other fastening mecha-
nism. It does not require the attachment surface be
secured to anything other than the illumination surface.
     The district court nevertheless read in a second fas-
tening mechanism—this one to secure the attachment
surface to the ballast cover. As discussed, the specifica-
tion discloses an embodiment for an energy efficient
lighting apparatus that can be retrofitted on an existing
fixture, and that embodiment describes a fastener that
connects the ballast cover to the attachment surface. See,
e.g., ’747 patent at 2:65–3:10, 9:1–10:28, Fig. 5. We do not
agree that this fastener limitation should be imported
into the claim.
    There is no suggestion in the specification or prosecu-
tion history that this fastener is important in any way
that would merit reading it into claim 12. In fact, in
describing the embodiment in Figure 5, the specification
explains that the fastening can be achieved by “many
different types of fastening mechanisms” including “an
adhesive strip” (think tape), “a magnet, clips, screws, etc.”
’747 patent at 9:40–51. It never refers to this run-of-the-
mill fastener as the “present invention” or “an essential
element” or uses any other language that would cause the
ordinarily skilled artisan to believe that this fastening
mechanism is an important component of the invention or
that it is critical to the invention for any reason. 2 See,


    2   This fastener is also mentioned in the “Summary
of the Invention.” ’747 patent at 2:65–3:10. The Sum-
mary of the Invention often spans many paragraphs,
columns, or even pages. In cases where we have held
limitations ought to be read in, it was not simply because
those limitations appeared in the Summary of the Inven-
tion. There was specific language that made clear those
limitations were important to the claimed invention. See,
6               BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



e.g., Luminara Worldwide, LLC v. Liown Elecs. Co., 814
F.3d 1343, 1353 (Fed. Cir. 2016) (noting we have found
disavowal or disclaimer based on statements such as “the
present invention includes” or “the present invention is”);
X2Y Attenuators, LLC v. Int’l Trade Comm’n, 757 F.3d
1358, 1362 (Fed. Cir. 2014) (noting we have held labeling
an embodiment or element as “essential” may constitute
disavowal and finding disavowal where the specification
stated a disclosure was an “essential element among all
embodiments or connotations of the invention”); Regents
of Univ. of Minn., 717 F.3d at 936 (finding disavowal
where the specification used the phrase “[t]he present
invention”); Verizon Servs. Corp. v. Vonage Holdings
Corp., 503 F.3d 1295, 1308 (Fed. Cir. 2007) (same); Hon-
eywell Int’l, Inc. v. ITT Indus., Inc., 452 F.3d 1312, 1318
(Fed. Cir. 2006) (same); SciMed Life Sys., Inc. v. Advanced
Cardiovascular Sys., Inc., 242 F.3d 1337, 1343–45 (Fed.
Cir. 2001) (same and “all embodiments of the present
invention”). We cannot discern, nor does any party argue
that there is, a technologically significant reason to have
the fastening mechanism secure the attachment surface
to the ballast cover. At oral argument, a number of
different, technologically unsophisticated mechanisms for
fastening were discussed. Oral Arg. at 20:10–20:35,
21:28–22:14. No party argued that the fastening mecha-
nism securing the attachment surface to the ballast cover
was an important feature of the claimed invention. Nor is
there any such suggestion in either the intrinsic or extrin-
sic evidence. To the contrary, the specification explains
the embodiment in Figure 5 is exemplary and non-
limiting. ’747 patent at 4:16–27, 10:29–32. It also ex-
plains that it is in “typical operation” that the attachment


e.g., Regents of Univ. of Minn. v. AGA Med. Corp., 717
F.3d 929, 936 (Fed. Cir. 2013) (finding disclosures in the
Summary of the Invention limiting where directed to
“[t]he present invention”).
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.            7



surface is secured to the ballast cover. Id. at 9:17–19. It
simply cannot be the case that every screw mentioned in
an embodiment of the specification must be read into the
claim. Without any evidence that the fastener is im-
portant, essential, or critical to the invention, it should
not be read in as a claim limitation.
    And possibly the most important reason why the fas-
tener for connecting the attachment surface to the ballast
cover disclosed in an embodiment ought not be imported
into the claim is because that limitation was originally
present in claim 12 and was expressly eliminated during
prosecution. Claim 12 was initially rejected under 35
U.S.C. § 102(b), and the applicant made responsive
amendments not relevant here. The examiner then had
an interview with the applicant. He prepared the exam-
iner’s summary of the interview, which stated the appli-
cant agreed to amend claim 12 “to resolve 112 issues.”
J.A. 56. That amendment deleted “ballast cover” and
replaced it with “illumination surface.” J.A. 54. That is,
the applicant expressly eliminated from the claim a
fastening mechanism that secures the attachment surface
to the ballast cover and replaced it with a fastening
mechanism that secures the attachment surface to the
illumination surface. The claim was allowed. No ordi-
nary artisan could read the prosecution history as any-
thing other than eliminating the requirement that a
fastening mechanism secures the attachment surface to
the ballast cover. No other possible reason was suggested
or alleged in this case.
    Defendants argue the prosecution history is ambigu-
ous because the examiner’s requirement that the change
be made “to resolve [§] 112 issues” provides no explana-
tion for the amendment. This argument is both factually
incorrect and legally irrelevant to how a skilled artisan
reading this history would understand the claim scope.
The examiner stated, and the applicant never contradict-
ed, that the amendment was required for § 112 reasons.
8               BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



Any skilled artisan would understand that if an examiner
requires an amendment for § 112 reasons it is an amend-
ment required for patentability. As a factual matter, no
skilled artisan would understand this claim to require a
fastening mechanism connecting the ballast cover to the
attachment surface when that very limitation was ex-
pressly removed from the claim to secure patentability
with the examiner’s blessing and agreement. We review
the prosecution history from the perspective of an ordi-
nary artisan and what he would understand from its
contents. The only takeaway here is that claim 12 needs
a fastening mechanism to secure the attachment surface
to the illumination surface, not to the ballast cover,
because this was the only change made at the examiner’s
request for § 112 reasons. A person of ordinary skill in
the art may not be able to divine what transpired between
the applicant and the examiner in that interview that
caused the change in claim language and scope. That is
irrelevant to the issue. We look at what an ordinarily
skilled artisan would understand about claim scope from
reading the prosecution history. See, e.g., Fenner Invs.,
Ltd. v. Cellco P’ship, 778 F.3d 1320, 1323 (Fed. Cir. 2015)
(“Any explanation, elaboration, or qualification presented
by the inventor during patent examination is relevant, for
the role of claim construction is to ‘capture the scope of the
actual invention’ that is disclosed, described, and patent-
ed.” (emphases added)); Biogen Idec, Inc. v. Glax-
oSmithKline LLC, 713 F.3d 1090, 1095 (Fed. Cir. 2013)
(“[T]he entirety of a patent’s file history captures the
public record of the patentee’s representations concerning
the scope and meaning of the claims.”); Hynix Semicon-
ductor Inc. v. Rambus Inc., 645 F.3d 1336, 1350 (Fed. Cir.
2011) (“Phillips counsels looking to the prosecution histo-
ry to ‘show what a person of skill in the art would have
understood disputed claim language to mean.’”); Arach-
nid, Inc. v. Medalist Mktg. Corp., 972 F.2d 1300, 1302
(Fed. Cir. 1992) (noting that claim scope is determined by
examining the prosecution history). And here, without
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.               9



question, the requirement that the invention as claimed
requires a fastening mechanism for securing the attach-
ment surface to the ballast cover was undisputedly and
unequivocally deleted from the claim.
     Defendants argue the preamble, “[a]n energy-efficient
lighting apparatus for retrofit with an existing light
fixture having a ballast cover,” requires reading in the
disclosed fastener for the claim to achieve its “retrofit”
function. A requirement such as this, according to De-
fendants, is sufficient not only to read into a claim a
limitation that is not present, but also to read into the
claim the precise mechanism by which that retrofitting
shall be achieved. The only claim at issue is claim 12, and
it is an apparatus, not a method claim. The apparatus
disclosed in claim 12 is structurally complete as claimed.
An apparatus claim is not required to include all elements
necessary for the claimed structure’s installation. This
claim does not recite how the lighting apparatus is in-
stalled into an existing light fixture, and it is not required
to do so.
   We have considered Defendants’ remaining argu-
ments and find them unpersuasive.
                          CONCLUSION
    We conclude the district court erred in construing “at-
tachment surface,” and adopt Blackbird’s construction of
“layer of the housing to which the illumination surface is
secured.” Because the court’s entry of judgment of nonin-
fringement was based on its erroneous construction, we
vacate the entry of judgment and remand for further
proceedings.
             VACATED AND REMANDED
                            COSTS
    Costs to Blackbird.
  United States Court of Appeals
      for the Federal Circuit
                 ______________________

    BLACKBIRD TECH LLC, DBA BLACKBIRD
             TECHNOLOGIES,
              Plaintiff-Appellant

                            v.

  ELB ELECTRONICS, INC., ETI SOLID STATE
LIGHTING INC., FEIT ELECTRIC COMPANY INC.,
             Defendants-Appellees
            ______________________

                       2017-1703
                 ______________________

    Appeal from the United States District Court for the
District of Delaware in Nos. 1:15-cv-00056-RGA, 1:15-cv-
00057-RGA, 1:15-cv-00058-RGA, 1:15-cv-00062-RGA,
Judge Richard G. Andrews.
                 ______________________

REYNA, Circuit Judge, dissenting.
    The sole issue on appeal is whether the “attachment
surface” in claim 12 must be secured to the ballast cover
of the existing light fixture. Because I conclude that the
district court correctly construed “attachment surface” to
mean “layer of the housing that is secured to the ballast
cover,” I respectfully dissent.
    Claim 12 does not expressly require that the attach-
ment surface be attached to anything other than to the
illumination surface. However, claim 12 does expressly
2               BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



describe a lighting apparatus “for retrofit with an existing
light fixture having a ballast cover.” ’747 patent col. 11 ll.
26–27 (emphases added). The majority fails to give
meaning to these claim terms by holding that “attach-
ment surface” means “layer of the housing to which the
illumination surface is secured,” and concludes that the
patent owner is entitled to patent scope that is neither
described in nor supported by the specification.
    The plain language of claim 12, read in the context of
the specification, implicitly requires that the attachment
surface be secured to the ballast cover to achieve the
retrofit function. Apart from the preamble, which the
parties agree is limiting, claim 12 contains no reference to
the ballast cover, the existing light fixture, or where or
how the apparatus is retrofit with the existing light
fixture. Because the only feature of the existing light
fixture described in claim 12 is the ballast cover, a person
of ordinary skill would necessarily conclude that the
attachment surface is secured to the ballast cover of the
existing light fixture. This would not be a big leap.
    The disputed term “attachment surface” appears only
in claims related to the retrofit function—namely claim
12, the disputed claim, claim 29, which describes a meth-
od for retrofitting a light fixture, and various associated
dependent claims. As the word “retrofit” in the preamble
of claim 12 implies securing the lighting apparatus to
something, it is reasonable to conclude that the “attach-
ment surface” is involved with achieving the retrofit
function.
     The structure of the claim language gives further
support that the “attachment surface” has a function
associated with the retrofit function. Along with the
“illumination surface,” the attachment surface is one of
two identified surfaces of the lighting apparatus’s hous-
ing, and is secured to the illumination surface via a
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.             3



fastening mechanism. See id. col. 11 ll. 28–29, 37–39.
The illumination surface has an explicit function in
addition to simply being secured to the attachment sur-
face, suggesting that the attachment surface likewise has
an additional “attachment” function other than attach-
ment to the illumination surface. See id. col. 11 ll. 30–31.
     Every single embodiment of the retrofit lighting appa-
ratus in the specification describes securing the attach-
ment surface to the ballast cover of the existing light
fixture. The specification expressly discloses retrofitting
by securing the attachment surface to the ballast cover in
the summary of the invention, see ’747 patent col. 2 l. 65–
col. 3 l. 10; col. 3 ll. 46–49 (describing “[a] method for
retrofitting a light fixture with an energy-efficient light-
ing apparatus,” in which “[t]he method also involves
securing the attachment surface of the housing to the
ballast cover” (emphasis added)), and in the embodiment
disclosed in connection with Figure 5, see id. col. 9 ll. 8–
10. In describing Figure 5, the specification states that
“[i]n typical operation, the attachment surface 530 is
secured to the ballast cover.” Id. col. 9 ll. 17–19. The
specification provides no other explanation for how the
lighting apparatus may be retrofit to the existing light
fixture. Taken collectively, these disclosures in the claims
and the specification—and the lack of any reference in the
intrinsic record showing the attachment surface being
secured to anything other than the ballast cover—teach a
skilled artisan that the attachment surface described in
claim 12 is secured to the ballast cover of the existing
light fixture. See MBO Labs., Inc. v. Becton, Dickinson &
Co., 474 F.3d 1323, 1329 (Fed. Cir. 2007) (“The words of
patent claims have the meaning and scope with which
they are used in the specification and the prosecution
history.”).
    The majority ignores the retrofit function that the at-
tachment surface plays in the lighting apparatus. See
4               BLACKBIRD TECH LLC    v. ELB ELECTRONICS, INC.



Medrad, Inc. v. MRI Devices Corp., 401 F.3d 1313, 1319
(Fed. Cir. 2005) (“It is . . . entirely proper to consider the
functions of an invention in seeking to determine the
meaning of particular claim language.”). Instead of
recognizing the attachment surface as it is described
throughout the specification—namely, to secure the
lighting apparatus to the ballast cover—the majority’s
construction merely parrots features of the attachment
surface, i.e., that it is attached to the illumination surface.
In doing so, the majority fails to give meaning to “at-
tached” beyond what is already described in the claim
language. See Apple, Inc. v. Ameranth, Inc., 842 F.3d
1229, 1237 (Fed. Cir. 2016) (“Ideally, claim constructions
give meaning to all of a claim’s terms.”). The majority’s
construction completely disregards the context in which
“attachment surface” is used, both in connection with the
retrofit function and the embodiments described in the
specification. The majority does not point to anything in
the specification describing a retrofit apparatus in which
the attachment surface is not secured to the ballast cover.
And there is no suggestion in the record that such an
embodiment was ever contemplated or possessed by the
inventor.
     The majority’s construction thus opens the door for
the ’747 patent to be subsequently invalidated for failure
to satisfy the written description requirement. Stated
differently, the majority’s construction is a route towards
rendering the patent invalid. See Carman Indus., Inc. v.
Wahl, 724 F.2d 932, 937 (Fed. Cir. 1983) (“Claims should
be so construed, if possible, as to sustain their validity. If
such a construction would result in invalidity of the
claims, the appropriate legal conclusion is one of nonin-
fringement, not invalidity.”).      The majority likewise
invites an enablement challenge; under the majority’s
approach, the retrofit aspect of the invention is merely an
afterthought, one for which a skilled artisan must figure
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.             5



out for themselves the means by which the retrofit func-
tion of the invention shall be achieved, without any guid-
ance from the patent. See Maj. Op. at 9. This result is
absurd, given that when the patent is read as a whole,
such guidance is clearly provided.
    Worse still, because the majority’s construction “does
not recite how the lighting apparatus is installed into an
existing light fixture,” id., the majority effectively reads
the retrofit function out of claim 12 and claim 29, the
retrofitting method claim. Claim 29, while not at issue in
this case, is instructive. See Phillips v. AWH Corp., 415
F.3d 1303, 1314 (Fed. Cir. 2005) (en banc) (“Because claim
terms are normally used consistently throughout the
patent, the usage of a term in one claim can often illumi-
nate the meaning of the same term in other claims.”).
Claim 29 contains the same “attachment surface” limita-
tion at issue in claim 12:
   29. A method for retrofitting a light fixture with
   an energy-efficient lighting apparatus, the light
   fixture having a ballast cover, the method com-
   prising:
       providing a housing having an attachment
   surface and an illumination surface, wherein the
   illumination surface comprises a plurality of illu-
   mination surface holes;
       providing a circuit board comprising a plurali-
   ty of light-emitting diodes;
       positioning the circuit board adjacent the
   housing so that the plurality of light-emitting di-
   odes protrude through the plurality of illumina-
   tion surface holes in the illumination surface; and
       securing the attachment surface of the hous-
   ing to the illumination surface, wherein the light-
   ing apparatus is coupled to a wall switch and
6               BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.



    wherein the illumination of the light-emitting di-
    odes is controllable based upon the position of the
    wall switch.
’747 patent, col. 12 ll. 52–60 (emphasis added).
    We cannot discount the importance of the retrofit as-
pect to the invention as a whole. The specification clearly
details the importance of retrofitting energy-efficient
lighting apparatuses into preexisting light fixtures as a
means of achieving energy savings without incurring
significant expense. ’747 patent, col. 9 ll. 5–10; col. 10 ll.
6–9. Yet the majority contends that claim 12, as an
apparatus claim, is structurally complete as construed
and need not describe the method of installation. Maj.
Op. at 9. But because the majority’s construction does not
disclose how the apparatus is installed, securing the
retrofit apparatus to the preexisting light fixture falls
outside of the scope of the claims. If “attachment surface”
is not construed as being secured to the ballast cover,
claim 29 utterly fails to disclose how the retrofit function
is to be achieved. As the district court properly noted
during the Markman hearing, the lighting apparatus for
retrofit “ha[s] to be attached to something” and cannot
“hover . . . like a ghost.” J.A. 254.
    The majority’s reliance on the prosecution history is
similarly misplaced. The prosecution history “can often
inform the meaning of the claim language by demonstrat-
ing how the inventor understood the invention” but “lacks
the clarity of the specification and thus is less useful for
claim construction purposes.” Phillips, 415 F.3d at 1317;
see also Grober v. Mako Prods., Inc., 686 F.3d 1335, 1341
(Fed. Cir. 2012) (“[W]hile the prosecution history can
inform whether the inventor limited the claim scope in
the course of prosecution, it often produces ambiguities
created by ongoing negotiations between the inventor and
the PTO.”). The original claim 12 reveals that, prior to
BLACKBIRD TECH LLC   v. ELB ELECTRONICS, INC.          7



amendment, the applicant understood that the invention
requires the attachment surface to be secured to the
ballast cover. See Phillips, 415 F.3d at 1317. Apart from
the amendment itself, the prosecution history sheds no
light on the purpose or effect of the amendment on claim
scope. I conclude that the amendment is ambiguous as to
the scope of the disputed limitation and has no effect on
the proper construction of “attachment surface” in claim
12. An ambiguous amendment, such as here, should not
negate the evidence in the specification and the conclu-
sion implicit in the claim language that the attachment
surface is secured to the ballast cover.
    Because the intrinsic record fully supports the con-
struction of attachment surface as being secured to the
ballast cover, I respectfully dissent.
