7 Centrifugal pumps and reciprocating positive displacement pumps; mud pumps; frac pumps; well service pumps; horizontal directional drilling pumps; oilfield production pumps; hydrostatic testing pumps; duplex steam pumps; fluid end assemblies for pumps and replacement parts therefor all for use in the oil drilling industry; Parts of oilfield wellhead machines, namely, fluid ends, and parts for fluid ends, in the nature of valve seat seals, seats, inserts, valves, springs, discharge covers, discharge cover seals, suction valve stops, suction cover, gauge covers, hammer union seals, gauge retainers, plungers, plunger clamps, discharge flange nuts, discharge flange spring gaskets, discharge flanges, pistons, and discharge flange seals