oil and gas well drilling, fracturing, stimulation, production and flow processing system components of metal, namely, manifolds; manually operated metal flow control valves, not being parts of machines; chokes of metal for regulating fluid pressures in oil and gas well drilling, fracturing, stimulation, production and flow processing systems; metal pipes, tubulars, pup joints and flowlines; flexible pipes comprising primarily metal parts; metal pipe couplings, connectors, unions and fittings...