In Blue Gentian, LLC v. Tristar Products, Inc., the Federal Circuit affirmed a district court’s correction of inventorship based on an unnamed inventor’s contribution of three key features, which features distinguished the claimed invention from the prior art. Responsive to an infringement suit by Blue Gentian, Tristar counterclaimed to include an unnamed Mr. Ragner as an inventor. The sole named inventor of the asserted patents had filed several patent applications on expandable hoses following Mr. Ragner’s demonstration of an expandable hose prototype. Blue Gentian argued that the district court’s analysis of the key features contributed by Mr. Ragner were “not sufficiently tied to specific claims.” The Federal Circuit disagreed, holding that the key features that Blue Gentian “itself acknowledges distinguish the invention of the asserted patents from the prior art are necessarily tied to the claims.”