by Dennis Crouch
In Focus Products Group International, LLC v. Kartri Sales Co., Inc., No. 2023-1446 (Fed. Cir. Sept. 30, 2025), the Federal Circuit reversed patent infringement findings against one defendant (Marquis Mills) while affirming most findings against another (Kartri Sales).
The most important part of the decision for patent prosecutors focuses on examiner driven restriction practice and how that can be used to define claim scope. The case also delves into trademark and trade dress issues that I leave for a separate post.
The patents at issue—U.S. Patent Nos. 6,494,248, 7,296,609, and 8,235,088—cover “hookless” shower curtains that attach directly to a shower rod through reinforced ring openings with slits. This integrated approach eliminates the need for separate hooks or clips. The representative claims recite shower rings with specific design features: a slit extending through the ring to an opening, and in some claims, a “projecting edge” that extends from the ring’s outer circumference. The accused products, manufactured by Marquis and sold by Kartri under the “Ezy-Hang” brand, featured rings with flat upper edges similar to Fig 21 above —a design feature that became the central battleground for determining infringement.
During prosecution of the ‘248 patent application, the examiner issued a restriction requirement identifying multiple patentably distinct species and defined those species through specific figure groups. Critically, the examiner distinguished “Species IV” (Figures 18-20, depicting rings with projecting fingers or extensions) from “Species V” (Figure 21, depicting rings “with a flat upper edge”). The patentee elected to pursue Species IV without objection – i.e., election without traversal. The patentee then rewrote the claims in a way that no longer focused on the flat upper edge. Except that one such claim slipped in — the patentee had added re-added a dependent claim that expressly “includes a flat upper edge” and the examiner asked it to be withdrawn as a non-elected species. Finally, in the notice of allowance, the examiner indicated that the non-elected claims had been cancelled as “drawn to a non-elected species without traverse;” and the applicant did no object to that characterization or seek reconsideration.
Eventually the Species IV patents issued without any claims focusing on the flat-upper-edge. However, the claim language was broad enough to encompass versions with both curved uppers and flat uppers. The question in the case then is whether the restriction procedure serves as an affirmative disclaimer of the flat upper scope. (more…)