The Milwaukee SHOCKWAVE™ 3Pc Automotive Impact Socket Set is made from impact duty, high quality alloy steel whcih provides strength and durability. Set includes 17mm, 19mm and 21mm with a ½” square drive. Most automotive services will require these sizes for wheel nuts. This set covers a large section of the passenger vehicle market. Each socket has a plastic retainer inside to prevent damage to wheelnuts. Recessed corners allow torque to be transferred across the flats of the socket rather than producing stress on the points or corners. Colour coded plastic sheath and lager size markings for quick size identification and additionally, the plastic sheath can be removed to gain a little more access.