Hollow Bolt,Stainless 1.ISO,ANSI,CE,JIS,DIN,BS& non- ... :4.8 ,6.8,8.8,9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the ... head,Countersunk head,Bugle head,Oval head,Hex flange head,Round head,Ball head,Button head... Socket typesPhillip type,Pozi type ...