... 6.8,8.8,9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the ... steel,Copper,Aluminum are available.Carton steel is high quality iron,such as 1022,1018,1010,1008 ... manufacturer with more than 20 years experiences in screw,bolt,nut,washer,rivet, stud, pin,wrench and so ... ,but is reasonable for products,it will spend high control force from material till products reach in ...