... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the specification of our ... Products ? MaterialsCarbon steel,Stainless steel,Alloy steel,Copper,Aluminum are available.Carton steel is high quality ... other materials accordingto customer's demand .Threads/ScrowsType "M","UNC","UNF","BSW"thread ... Countersunk head,Bugle head,Oval head,Hex flange head,Round head,Ball head ...