Description Toilet Flush Valve Seal 1-7/8-inch Outside Diameter 15/16-inch Inside Diameter 1-5/16-inch Lip Diameter (47mm) Outside Diameter (24mm) Inside Diameter (34mm) Lip Diameter All these dimensions are equivalent to one another, respectively. This replacement seal is made of silicone material to provide the best and tightest fit to your flush valve or flapper valve. This replacement seal can be used for a flush valve or a flapper valve, this is why the measurements of the outside diameter, and the inside diameter are very important. This is to ensure that your toilet does not leak any water when flushing.