Feature:1. High temperature quenching, resistant to rust and corrosion, rugged and durable, strong torsion.2. The hardened chrome‑vanadium steel socket improves rotation efficiency and reduces wear.3. There is a precise chamfer at the end of the bit, which can be inserted smoothly.4. The size is printed on the socket for easy identification, bring much convenience for you.5. Including a variety of bits with different specifications, completely meet your different needs.Specification:Item Type: Wrench Socket BitMaterial: Chrome-Vanadium SteelSquare Wrench Drive Size: 1/2in, 3/8inSpecifications of Hex Bits:T20 T25 T30 T40 T45 T50 T55 (length: approx. 30mm/1.2in)T20 T25 T30 T40 T45 T50 T55 (length: approx. 75mm/3in)H4 H5 H6 H7 H8 H10 H12 (length: approx. 30mm/1.2in)H4 H5 H6 H7 H8 H10 H12 (length: approx. 75mm/3in)M5 M6 M8 M10 M12 (length: approx. 30mm/1.2in)M5 M6 M8 M10 M12 (length: approx. 75mm/3in)Quantity: 40pcs/setSuitable for: 1/2in and 3/8in square wrench drive/air impact wrench/power rod, etc.Application: Household, automobile, etc..Package List:40 x Bits1 x Tool BoxNote:Please allow 1mm error due to manual measurement. Thanks for your understanding.