The Federal Circuit affirmed summary judgment and trial opinions regarding patent infringement and trademark infringement matters related to stethoscopes. 3M filed suit against Pradeep Mohan asserting trademark infringement due to Mohan’s use of marks confusingly similar to 3M’s LITTMANN, CARDIOLOGY III, and MASTER CARDIOLOGY marks. The lawsuit also included claims of patent infringement based on a proprietary ear tip technology 3M alleged Mohan used. The District Court granted summary judgment that Mohan infringed 3M’s patent and that the trademarks CARDIOLOGY III and MASTER CARDIOLOGY were valid marks. After a bench trial, the District Court found willful trademark infringement and awarded attorneys’ fees. Mohan appealed. The Federal Circuit affirmed.