Mansfield Flapper fits several models and is the replacement flapper for Mancessa toilets with the rubber strap instead of a chain. Measures 3" across. 006300173, 6300173 Mansfield / Mancessa Flapper 630-0173. The package has a card to let you know which insert to use in tour Mansfield toilet model. It is flexible rubber and is easily installed buy putting the rubber hoop over the "ears" on the side of the flush valve. The Mansfield 630-0173 flapper does measure 3 inches across but is classified as a 2 inch flapper because the flush valve is 2 inches in diameter.