Keeney Manufacturing K832-2 Plumb Pak Flat Flush Valve Shank Washer, Rubber, 3/4 in H X 5-1/2 in W, Black 3-Inch Flush valve shank washer Fits Toto, Gerber, Mansfield, Crane, Jacuzzi toilets or any flush valve with similar thread size Rubber Flat style with ribs Black