... bag carton material: Carbon steel, Alloy steel, stainless coach screw bolt:M3-M22*length5mm~160mm nut:M3-M30 Washer:M3-M30 ... ,bike, machine, industry,military,metallurgy,medical machinery,survey,corrosion Our high-quality products are manufactured as ASTM , AMS and others . - As ... steel. Believe us,choose us.Time will tell everything. Coach Bolt DIN603