square inner 3/8 "- outer 1/4"
Greater durability. Fortum socket wrenches are cast from chrome-vanadium steel 61CrV5 and modified on NCS machines hardened in oil and hardened around the perimeter to achieve optimal hardness and strength of the thin-walled structure. 61CrV5 and 61CrV4 (also referred to as 6150 and 6140) is the highest grade of chrome-vanadium steel. Hardened and surface-treated with matt hard chrome to achieve optimum surface hardness and corrosion resistance, this steel is used for all parts except the most exposed ones.
Main technical parameters: