7 Back pressure valves as parts of machines; Filters for pumps, pneumatic, and hydraulic machines; Pneumatic air preparation equipment, namely, airline filters, lubricators, and regulators, all being parts of machines; Pumps and compressors as parts of machines, motors and engines; Pumps as parts of machines, motors and engines; Taps; Valves being parts of machines; Ball valves being parts of machines; Pneumatic air preparation equipment, namely, airline filters, lubricators, and regulators, all being parts of machines; Self-lubricating mechanical friction parts, especially of composite materials, namely, wear rings, washers, bushings, spherical bearings, bearing pads, sliding blocks and machine transmission gears all for load bearing machines, conveyors, handling trucks and machines, lifting machines, agricultural machinery, construction equipment machines and hydraulic turbines