The Flushmate III M-101526-F32 replacement system is designed to replace the Flushmate M-101526-F3 503 Series models for Kohler K4404 toilets. The Flushmate III M-101526-F32 1.6 GPF replacement system, is designed to replace the Flushmate M-101526-F3 1.6 gpf 503 Series models for two-piece Kohler K4404 toilet fixtures. The Flushmate III M-101526-F32 includes the Flushmate M-101526-F3 complete system with locknuts and gasket to install in your toilet tank. The Flushmate III M-101526-F32 1.6GPF replacement system is designed to only work with existing Kohler K4404 pressure assist toilets that were originally equipped with the Flushmate III M-101526-F3 1.6 GPF system.