The Kincrome Premium Impact Screwdriver Set is designed specifically for effective fastening and loosening of rusted, damaged or stripped fasteners in heavy-duty applications, such as larger fasteners used on a car or industrial machinery. It does this by applying a strong, sudden rotational force coupled with forward thrust when struck with a hammer to 'shock' fasteners loose and prevent the tip from camming out of the fastener. It utilises 5/16" hex drive bits and features a moulded body and hand protector for added grip and shock absorption and a steel end-cap for striking with a hammer. It also features a removable bit holder covering the 1/2" square drive which once removed allows the impact driver to be used with 1/2" drive impact sockets. The contents of the set are all housed neatly in a Kincrome BMC for easy transportation and to prevent lost bits! To use the impact driver, simply select the Kincrome PTA bit that suits the application, place the tip into the fastener and apply light rotational pressure in the direction that you wish to turn the fastener in order to engage the tool mechanism. maintain light rotational pressure and strike the end-cap with a hammer using your other hand. A few hits should tighten or loosen the fastener as required.