Common metals and their alloys; Alloys of common metal; Mechanical fastening elements of metal; Small items of metal hardware, namely, pipes, tubes of metal, pipe access fittings, nozzles, metal test coupons, test racks of metal for monitoring corrosion, metal test coupon holder assemblies, fasteners, washers, spacers, wear test specimen, fracture mechanics specimen, sealing gaskets, and metals used as mechanical test specimen