Developed for square drives - You can use the PRO Impact socket set for hexagon head screws, bolts and nuts with your square drive spanner. The PRO Impact socket set is made of heat-treated chrome-molybdenum steel and is highly resistant to high torques thanks to its thick walls. The black phosphate coating protects it from rust and corrosion. The sockets are laser-marked and colour-coded so that you can find the right one at first glance. They have a groove and a through hole. They can be attached to your impact wrench with a pin and ring for an extra-strong hold.