Metric Fasteners Brass Metric Fittings : Material : Brass to BS 2874 / 2872 SS 304 316. Finish : Brass Metric Fasteners Stainless Steel metric Fasteners Fittings are available in natural, Electro-Tinned, Nickel etc. Threads : ISO Metric, BSW, BA, BSF, UNC, UNF UNEF etc. Sizes : M4, M5, M6, M8, M10, M12, M14.