... ,6.8,8.8,9.8..... DRYWALL SCREW,WOOD SCREW,CHIPBOARD SCREW. A good non-standard fastenerS manufacturer for your better ... :Self tapping threads "A","AB", Threads for chipboard screw,wood screw,drywall screw;Type "M","UNC","UNF","BSW"threads for Machine threads ... are used in most of places such as drywall,concrete,chipboard,machine,wood...2) Main export market:North America,South America ...