Klein Tools 70220 Reversible Impact Driver Set Rugged, hand-impact driver turns rusted, frozen, or other stubborn screws Includes 3/8-Inch (10 mm)-square-drive fitting adapter for 5/16-Inch hex bits and four assorted hex screwdriver bits (5/16-Inch (8 mm) and 1/2-Inch (13 mm) regular slotted tip, #2 and # 4 Phillips-tip) Can also be used on 3/8-Inch (10 mm) square-drive impact sockets Internal, spring-loaded, helical design transforms the impact of a hammer blow to up to 200 foot-pounds of shock torque Easily reverses for tightening or loosening screws