... 8.8,9.8..... Hollow Bolt,Stainless Steel Hollow Bolt,Bolt with Internal Thread.1.What’s the specification ... .Threads/ScrowsType "M","UNC","UNF","BSW"thread are available. Head typesHexagon head,Mushroom head ... are a professional manufacturer with more than 20 years experiences in screw,bolt,nut,washer,rivet, stud ... , pin,wrench and so on .2.Our company had good reputation with ...