1/2 Inch Drive Toolzone Impact Driver Set for cracking off/removing those seized screws. This tools is to be used in conjunction with a hammer. You place the correct bit size on the Driver, place it on the screw to be removed then hit the Driver hard with a hammer to loosen the seized screw. Heavy Duty 1/2 inch Drive Impact Driver. With Comfort Grip. Bolster Style Handle. Contains 13 Bits in Sizes: Ph: 1, 2, 3 & 4 Slot: 5, 6, 8, 10 & 12mm Hex: 4, 5, 6 & 8mm. 1/2 inch square drive to 8mm HEX Adaptor. Storage Case. Brand: Toolzone. .