API 7K Hydraulic Cylinder Fluid End Module for F‑Series Triplex Mud Pump Spare Parts Description Hydraulic Cylinder is the main part for fluid end of the mud pumps.The hydraulic cylingder of mud pumps under different brands are also not all the same.Such as the famous brands of BOMCO, EMSCO, GARDNER DENVER, OILWELL,NOV, etc.The similar mud pumps model of theirs, the parts are not all the same.But all of they must use hydraulic cylinder. And other spare parts will be assembly