Features: *The screwdriver bits are made of alloy steel with heat treatment, HRC52-55,good toughness and wear resistance. *The screwdriver bits are 150mm/6" long, suit for poket hole jig woodworking. *Magnetic heads can firmly fix screws, protect both screws and bits. *1/4" 6.35mm hex shank fit for electric screwdrivers,hand screwdrivers, electric drills, air drills etc. Specifications: Product name: Square Head Screwdriver Bits Set Material: Alloy Steel Color: Silver(As shown) Bit Type: Square Head Magnetic: Yes Length: 150mm / 6'' Shank: 1/4Inch (6.35mm Hex) Size: SQ1, SQ2, SQ2.5, SQ2.74, SQ3, SQ4, SQ5 Suitable for: electric screwdrivers, manual screwdrivers, electric tools Exercises, air drills, etc. Optional: 7pcs set Package Contents: 7 × Screwdriver Bits Notes: 1.Transition: 1cm=10mm=0.39inch. 2. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 3. Please allow slight manual measurement deviation for the data.