Description 2.5-inch Flush Valve for One-piece Toilets for use with Briggs SP-88 75 Model 3200 & 5188, 2.5-inch flush valve for one-piece toilets. 62.15 mm or 2.44-inch flush valve for one-piece toilets with 2.5-inch flush hole (common measurement for hole inside tank). Model # 3200 Model # 5188. Can work with other toilet manufacturers with 2.5-inch toilet tank flush holes. Flush Valve Easy Measuring Tips – Video One piece or Two piece which is right for you? Video