... to 9mm Material: carbon steel,alloy steel Surface:blackened Proof Coil Chain ASTM 80/G30 We can supply various kinds of ... steel,alloy steel,high-quality alloy steel,stainless steelSurface:self-color, polishing,blackened,pained,plastic coating,hot-dipped galvanized,electro galvanized ... make the non-standard chain according to your requirements. Proof Coil Chain ASTM 80/G30