Teng Tools impact sockets are specifically designed for use with power tools and air tools. Manufactured in chrome molybdenum in accordance with GGG-W-6608, these sockets ensure the highest quality. They are size marked for easy identification. These regular 6-point deep impact sockets have a 1/2 inch square drive. They are manufactured to the latest DIN standard for industrial use.The TEN920621 Impact Socket has the following specifications:Size: 21mm. Length: 78mm.