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 Bit Material: Chrome-Vanadium Steel Square Wrench Drive Size: 1/2in, 3/8in Specifications 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/set Suitable 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 Box Note: Please allow 1mm error due to manual measurement. Thanks for your understanding.