... good Aluminum,R200...Meanwhile,we can use other materials accordingto customer's demand .SizeThe Diameter :Generally,it is M1-M16 in ... screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads.Head typesHexagon head,Mushroom head,Pan head,Countersunk head ... head,Oval head,Hex flange head,Round head,Ball head,Button head...Socket typesPhillip type,Pozi type,Eleven type,hexagonal type ...