Tank for Allerton 1.28 gpf toilet (biscuit) 12 rough-in. This toilet features Fluidmaster fill valve, 3 flush valve and 2 fully glazed trapway for reliable, complete flush every time. The Siphon Jet technology is quiet and helps keep the bowl clean. Use with HE-21-577-09 (Elongated, Ergoheight bowl), HE-21-542-09(round front bowl), or HE-21-572-09 (Elongated bowl)