General description This set includes 8 pieces of 4-inch long hex head Allen drill bits, designed for use with various screwdrivers and electric tools. The bits are magnetizable, allowing for easy screw handling when magnetized. Technical specifications Material: High quality S2 steel Head type: Hex head Total length: 4 inch / 100 mm Shaft type: 1/4 inch hex / 6.35 mm Sizes included: H2.5 (2.5 mm), H3 (3 mm), H4 (4 mm), H5 (5 mm), H6 (6 mm), H8 (8 mm), H10 (10 mm), H12 (12 mm) Usage Compatible with electric screwdrivers, manual screwdrivers, electric drills, and general tool sets. Using the correct size screwdriver bit minimizes damage to both the screwdriver and the screw. Other information Exquisite workmanship ensures precise locking of screws without damaging them or the screwdriver head. Allows increased torque when tightening screws. Note: Manual measurement may result in slight variations.