3.5 inch Flush Valve for One Piece Toilets with 3 Locking Lugs. Comes with Solid Silicone Flapper. The Valve Has a 3.3 inch Diameter that fits inside a 3.5 inch Flush Hole. Make sure you Measure your Toilet Flush Hole before Ordering One piece Toilet Flush Valves. Easy to Remove and Replace One Piece Toilet Flush valves by NuFlush.