... would like to Grade4.8,6.8,8.8,10.9,12.9 and others you needMaterial 45#, 40Cr, 35CrMoA, 42CrMoA ... M42 LengthM16-300Type of headSquare,Hex,Flange,Hex socket,T-Head and other you can chooseSurface treatmentBlack Oxide,Zinc ... to Nuts Type of NutSquare,Hex,Flange,Hex socket,T-type,Coupling,wheel ,acorn,tapper,and so onRegarding ... have 10years experience of manufacturing fasteners Carbon Steel Nut Grade 2H