spring nut Material:A2,A3,A4,AL,Copper Finish:Zinc,Black,Hdg etc Size:M2-M72... ... ,BS,ASTM,SFS,GB,NON-STANDARD etc2.Material:Carbon steel,A2,A3,A4,Copper,Aluminum etc3.Finish:Zinc plate,Black,HDG etc4.PackingWe ... establish long-term cooperation with you,If you are interested in any of our products,please dont hesitate to contact us ...