Used in conjunction with a standard air hammer at low pressure and 5/16"(8mm) Hex bit. Vibration shakes the screw loose doing the hard work for you, while rotation is applied with the handle. Ideal for corroded, countersunk, overtightened and painted screws. No more stripping of screw heads. Features & Benefits:Used in conjunction with a standard air hammer at low pressure and 5/16"(8mm) Hex bit.Vibration shakes the screw loose doing the hard work for you, while rotation is applied with the handle.Ideal for corroded, countersunk, overtightened and painted screws.No more stripping of screw heads.Model No. VS0291 Specifications: Model No VS0291 Brand: Sealey Nett Weight: 0.20kg Shank Size: .401" Parker Taper Bit Size: 5/16"(8mm), Bits not included