Pressure relief valve for overload protection. SEE LAST PHOTO FOR ADDITIONAL DETAILS. THE PUMP FOR SALE HERE (MODEL # 5AS60) IS THE FIRST LINE ON THE CHART. _gsrx_vers_841 GS 7.0.16 (841). The item "Williams by Snap-On 10000 PSI Air Pneumatic Powered Hydraulic Pump Foot Switch" is in sale since Thursday, December 20, 2018.This item is in the category "Business & Industrial\Hydraulics, Pneumatics, Pumps & Plumbing\Pumps & Pump Accessories\Hydraulic Pumps". The seller is "jonathancmu" and is located in Newport, Michigan. This item can be shipped to United States.