The General Pump 701013 replaces a plastic disc inside pumps and pulse pumps. It is compatible with model 100152 pulse pumps and EZ Series 44, EZ Series 44 E, T Series 47 S, TC Series “60”, TT 51 Series, U, UI Manifolds, and HTS Series pumps. Dimensions of the O-ring measure .426 ID x .070 CS. Made with Buna-N and a 70 Duro hardness. A genuine OEM part. Ensures a proper fit and material compatibility.