Abstract: A speaker system can include a speaker core and a removable jacket. The speaker core can have a housing and a speaker positioned within the housing. The removable jacket can cover the speaker on an outside surface of the housing, the jacket extending along at least three sides of the housing. Among other features, the speaker core can be used with one of among a number of different jackets to form different speaker systems.

Abstract: A fluid check valve consisting of a pair of leaflets contained within an annular body member (10). These leaflets (16 and 17) open and close hemodynamically as a reaction to the natural pumping action of the heart. They open from the center outward based upon their S shape profile (45). Blood flows through the interior surface (12) of the annular body member and leaflets. These leaflets open and close relying upon, protruding rails from the annular body member (20 and 21) and their integrated stop means (31-38). The protruding rails guide the leaflets in a floating pivot action that virtually eliminates area of stasis and prevent thrombosis.