1. material: stainless steel 2. best price, good quality and service Process Capablilities StandardISO, GB, DIN, JIS, ANSI, BSW, ASMEGrade3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 etc.SizeM0.8~M12MaterialStainless, Steel,Brass, Steel,Bronze, Iron,Aluminum,Carbon steel,Alloy steel, silicon bronze,etc.Head/Tread stylesAccording client's requiresCoating/Surface treatmentZinc,Tin,Sn/Pb,Nickel, ...