... screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads.Head typesHexagon head,Mushroom head,Pan head,Countersunk head,Bugle head,Oval head,Hex flange head,Round head,Ball head,Button head ... control,good at modern concept of management.3. We have special research person and more than 100 equipment to produce fastener ...