I don't remember my tank part number right now but it's a Cadet 3 1.6gpf 10" rough in which had a leaky tank right out of the box. I bought the FM 3" flush valve just in case the replacement tank leaked also. I used the flush valve gasket from the kit. I can tell you that the FM sponge gasket under the tank wasn't the same height. IIRC correctly it's taller and I used the OEM. I have it and can measure it if you care to know.