Impact screwdriver. 12.5 mm (1/2″) square drive. (For mounting 12.5 mm (1/2″) square drive power socket spanner inserts). Especially suited for loosening stuck screws by striking with a hammer. For clockwise and anti-clockwise loosening Contents: 1 impact screwdriver, 12.5 mm (1/2″) square drive, reversible 1 bit ea. for 7.94 mm (5/16″) slotted head screws in 8 x 36, 8 x 80, 10 x 36 mm 1 bit ea. for 7.94 mm (5/16″) Phillips (PH) screws in 2 x 36, 2 x 80, 3 x 36 mm 1 link, 12.5 mm (1/2″) internal square to 7.94 mm (5/16″) hexagon socket