Gerber 99-770 or G0099770 Flapper For some Gerber 3 Inch Flush Valves. This flapper is also stamped WDI B4802-1 on the top. This flapper also has a blue insert in the bottom. It also fits several different brands, such as universal Rundle, Aqua Source, and Jacuzzi toilets. It is also the Crane PO30750 And The Briggs 4802-1. Aqua Source number is RT82102F. This flapper fits Aqua Source models 98923,312795,352027,395280,12293. This flapper also takes the place of the Gerber 99-827 flapper.