Mechanic's 20 Piece Set Contents: Slotted: 8, 9, 12, 14, and 16mm. TX: T20, T25, T27, T30, T40, T45, T50, T55 and T60. Crosspoint: No.2, 3 and 4. PZ: No.2, 3 and 4. Used most often in the automotive and aerospace industries. The weight to strength ratio ensures the reliability and ccessibility that is so important in this type of production environment. For insertion and removal of fasteners and fixings using 1/2"square drive tooling. Unique knurled body gives extra grip which is essential for a quick tool change when your hands are greasy/oily. Registered Design No. 2053516UK. Manufactured from chrome vanadium steel and are fully chrome plated with a mirror finish and aluminium-free. All have ball retaining groove on each face of the square drive. Conform to DIN standards. Overall length: 55mm. Bit length: 20mm.