Proto J5221MH Standard Socket, 3/8" Drive, 6 Points, 21mm, Chrome, 1-15/64" OAL

• Proto 6 Point Sockets are ideal for use on stubborn or damaged fasteners, and also on fasteners made from soft materials.
• The TorquePlus design is a high performance drive configuration which allows for quick and easy socket engagement to the fastener flats, not the corners.
• The TorquePlus configuration employs a radius-corner design, shifting contact area and stress away from the fastener corners and distributing contact stresses over a large area of the socket, minimizing slippage.
• The TorquePlus internal design minimizes fastener rounding, helps to extend fastener life, and allows the user to more easily turn worn, rounded, or rusted fasteners.

These 3/8" drive metric sockets have a three-eighths inch square drive that's compatible with drive tools of the same size. They come in metric sizes that are measured in millimeters to fit fasteners with a metric size head.