Regulating unloader mounts directly on each pump to assure system pressure control and pump protection. Convenient multiple porting provides installation flexibility. Maximum flow: 4.0 GPM. By pass port: 3/8 FPT. The item "CAT PUMP MODEL 4SF40GS1 4 GPM 3500 PSI FITS 1 GAS ENGINE SHAFT" is in sale since Wednesday, August 23, 2017.This item is in the category "Home & Garden\Yard, Garden & Outdoor Living\Outdoor Power Equipment\Pressure Washers". The seller is "prontopsisupply" and is located in Seneca, Pennsylvania. This item can be shipped to United States.