... Grade:4.8 ,6.8,8.8.. Special screw,special head screw,special machine screw 1.What’s the specification of our Products ... can use other materials accordingto customer's demand .ThreadType "M","UNC","UNF","BSW"thread are available.Head typeHexagon head, ... as drywall,concrete,chipboard,machine,wood...2)Main export market:North America,South America,Eastern Europe,Asia,Western Europe .3)Service:OEM service ...