Hollow Bolt,Stainless 1.ISO,ANSI,CE,JIS,DIN,BS& ... 4.8 ,6.8,8.8,9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the ... steel,Alloy steel,Copper,Aluminum are available.Carton steel is high quality iron,such as 1022,1018,1010,1008,1015... ... other company,but is reasonable for products,it will spend high control force from material till products reach in customer hands ...