Mr. Stevenson submitted a collection of five affidavits. The five affiants are all experienced skateboarders with competitive experience, some professional. The affiants all have ridden flats, rockers, and kicktails and all find the kicktail to be superior to the others. The affiants all agree that far greater maneuverability is possible with the kicktail. They all cite particular problems of imbalance associated with the rocker board.
2) Commercial Success
The brief for the Taiwan manufacturers improperly asserts that commercial success can only tip the scales in favor of patentability in close cases. The eases cited by the Taiwan manufacturers, Digitronics Corp. v. New York Racing Association, Inc., 553 F.2d 740, 193 USPQ 577 (2d Cir. 1977), International Telephone and Telegraph Corp. v. Raychem Corp., 538 F.2d 453, 191 USPQ 1 (1st Cir. 1976), and cases cited therein, support their view that “[o]nly in a close case, in which application of the subjective criteria of nonobviousness in 35 U.S.C. § 103 does not produce a firm conclusion, can these objective or secondary considerations be used to ‘tip the scales in favor of patentability.’ ” Digitronics, supra at 748, 193 USPQ at 584. Contrary to the statement in Digitronics, we find nothing in Sakraida v. Ag Pro, Inc., 425 U.S. 273, 96 S.Ct. 1532, 47 L.Ed.2d 784, 189 USPQ 449 (1976) that “laid to rest” the view followed by this court and enunciated in Graham v. John Deere Co., supra, 381 U.S. at 17, 36, 86 S.Ct. 684, 148 USPQ at 467, 474. The inference of obviousness drawn from prior art disclosures is only prima facie justification for drawing the ultimate legal conclusion that the claimed invention is obvious under 35 U.S.C. § 103. Therefore, it is necessary that such secondary considerations also be evaluated in determining the final validity of that legal conclusion. As presented in John Deere, such secondary considerations may serve to “guard against slipping into hindsight” and “to resist the temptation to read into the prior art the teachings of the invention in issue.”
The AU found as fact, and it has been undisputed by either party, that presently kicktail skateboards constitute approximately 90-95% of production and sales in the skateboard industry. It is also clear from the record that the only difference between appellant’s kicktail skateboard and the prior art flat skateboard is the provision by appellant of “an inclined foot-depressible lever coupled to the rearward end section of the platform.” Appellant has submitted five affidavits of experienced competitive skateboarders to attest to the fact that the kicktail is superior and provides far greater maneuverability than the flat or rocker boards. The survey of the members of the Pro-Am Skateboard Racing Asso. supports these affidavits by showing a decided preference for the kicktail because of its functional attributes. We also note that the majority opinion of Commissioners Moore and Bedell, as well as the ALJ, found the kicktail to possess functional advantages over the rocker. See n.3 supra. These factors establish prima facie a nexus between commercial success and the merit of appellant’s invention, the provision of an inclined foot-depressible lever. In re Felton, 484 F.2d 495, 179 USPQ 295 (CCPA 1973); In re Caveney, 386 F.2d 917, 55 Cust. & Pat.App. 721, 155 USPQ 681 (1967).
In rebuttal, to show that the commercial success is unrelated to the merits of the invention, appellees have presented one witness, Mr. Langton, who gave his opinion that the commercial success was due to cosmetic reasons. Appellees presented one other witness, Mr. Criswell, who was not sure why kicktails have captured so large a segment of the market. Mr. Criswell is a highly proficient skateboarder who uses the kicktail because it helps him to know where his foot is. We earlier noted that Mr. Cris-well, like Mr. Langton, has a personal financial interest in kicktail skateboards.
Thus, appellees have chosen to rebut appellant’s prima facie nexus between commercial success and the merit of his invention with the opinion testimony of a single witness with a demonstrated financial interest in the outcome. As noted earlier, we