Gerber 3" FLAPPER Fits Gerber and Crane

Genuine Gerber 99-788 Flapper Used in several HET High Efficiency Toilet Models. It does not have the extra hole on the underside like the 99-770. The flapper Measures about 3 and 5/8 inches across the top. 

Also fits - CRANE 1 PC 3" Flush Valves