18V Cordless Impact Wrench, 400Nm, 1/2 Inch Square Drive

This is the tool for bolts that will not move: wheel nuts on a lorry or a matatu, U-bolts on a leaf spring, shackle pins, structural bolts on a steel frame, and anything that has sat outside long enough to rust into place. An impact wrench does not push against your arm the way a breaker bar does. It delivers the force in short hammer blows through the drive, which is why it shifts a nut that a spanner will not.

Four hundred newton metres of fastening torque covers bolts from M14 up to M32. The motor turns at up to 2 400rpm and the mechanism delivers up to 3 200 impacts a minute, so a nut either comes loose in the first few seconds or it is seized beyond what a hand tool would have managed anyway. The half inch square drive is the standard size for impact sockets, so sockets are easy to find. A hog ring holds the socket on the anvil so it does not drop off under the hammering. There is an LED work light for under a vehicle and a belt hook for carrying it.