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