The KISSLER Flapper Fits Toto Brand 14U366 is a toilet tank flapper replacement part that fits Toto toilets. It is made of rubber and measures 3-1/2" diameter x 1-1/4" tall. This flapper is chlorine-resistant and features a twist seal design. It is designed as a direct replacement part for Toto model #THU296, THU366, THU368, THU373, THU393, and THU394 toilet models. This flapper valve allows the toilet tank to seal and hold water until flushed.