the lower valve and upper valve guide is for EMSCO, OILWELL, GRADNER DENVER,NATIONAL, etc ... parts, mud pump expendables, and Mud Pump spares. We supplies top quality O.E.M. interchangeable mud pump parts for ALL ... , Liners, Pistons, IDECO, National, Oilwell, OPI, Skytop, Wheatley, and Wilson. Lower and upper Valve Guide