21mmFeatures and Benefits: Made of high quality steel (chrome-molybdenum) Unique hex opening on each end so that a single socket can accommodate two hex sizes Thin wall design to fit most recessed wheel nuts Designed for auto and light truck wheel fasteners Engineered specifically for use with impact tools, using the most up to date industrial specifications Each socket is thoroughly made with the correct balance of strength and durability and is tested to the highest specifications to deliver outstanding performance at the most competitive cost. Use with 1/2" drive extended shank impact tools