... screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads.Head typesHexagon head,Mushroom head,Pan head,Countersunk head ... control,good at modern concept of management.3. We have special research person and more than 100 equipment to produce fastener ... used in most of places such as drywall,concrete,chipboard,machine,wood...2) Main export market:North America,South America,Eastern ...