The Milwaukee SHOCKWAVE IMPACT DUTY steel (Chrome-Molybdenum) is high quality alloy steel that provides ultimate strength and durability. This universal joint features best fitting thanks to 6 gripping points and non-slip hex geometry to prevent socket and fastener rounding. The deep wall construction provides clearance for protruding bolts. Markings are stamped and ink filled for diameter and laser etched for wear resistance. It also includes a dual hole design and groove for security accessories.