Screws:self tapping screws,self drilling screws, machine screws, chipboard screws drywall screws, assembled screws, hanger screws, dowel screw etc., Raw material:steel, stainless steel, plastics Size:#4 to M20(4# to 3/4? Hardened and without hardened Surface treatment: plain, black, phosphate, nickel, zinc, hot dip galvanized, dacromat, mechanical galvanized, Cr+3