Combination Wrenches: The materials include 40# chromium-vanadium steel,45#carbon,40#chromium steel,20#chromium-manganese-titan Combination Wrenches:The materials include 40# chromium-vanadium steel,45#carbon,40#chromium steel,20#chromium-manganese-titanium steel,55#chromium-molybdenum steel,35#carbon steel,etc.