... , Top Spring, None Spring.-2) Physical performance, machenical properties, and material:a) normal strength: made from low carbon steel, C1015, Q235 ... steel such as C1035, C1045, etc, And with hardened treatment.-material: carbon steel, stainless steel, SS304, SS316. etc.-3) Surface treatment ... /CARTON, 36 or 48 cartons/Pallet. Steel Spring Nut of strut channel