... 9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the specification of our Products ? MaterialsCarbon ... customer's demand .Threads/ScrowsType "M","UNC","UNF","BSW"thread are available. Head typesHexagon head,Mushroom head,Pan head, ... ,hexagonal type,Torx type,trangle type,slotted point type,square type,Combined type... FinishZinc plated,Nickel plated,Dacroment Plated ...