... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the specification of our Products ? ... customer's demand .Threads/ScrowsType "M","UNC","UNF","BSW"thread are available. Head typesHexagon head,Mushroom head,Pan head ... type... FinishZinc plated,Nickel plated,Dacroment Plated,chromium plated,Tin plated,Black phosphating ,anodized ,Parkerising,and Environmental Plated is ...