... .Grade:4.8 ,6.8,8.8.. Special screw,special head screw,special machine screw 1.What’s the specification of our Products ? MaterialCarbon ... be packing as per the customer's requests .additional process Washer assembly,Heat treatment,Baking hydrogen,Anti-slipping patch can be ... professional manufacturer with more than 20 years experiences in screw,bolt,nut,washer,rivet, stud, pin,wrench and so on .2.Our ...