1Made from premium chrome vanadium steel, it is durable, of high strength and good abrasion resistance durable 2Ball bearing on head holds sockets securely 31/4in, 3/8in, 1/2in hex shank fits well with many electric drill 4Change your hand socket set into a driven socket with different size 5Nickel plating extension bars set can be used for a long time These adapters are handy for attaching a socket sets, ratchet sockets, socket wrench, ratchet universal sockets to an electric drill. Features: Made from premium chrome vanadium steel, it is durable, of high strength and good abrasion resistance durable. Ball bearing on head holds sockets securely. 1/4in, 3/8in, 1/2in hex shank fits well with many electric drill. Change your hand socket set into a driven socket with different size. Nickel plating extension bars set can be used for a long time. Specifications: Condition: 100% New Material: Chrome Vanadium Steel Color: Multi-color Size: 1/4in(6.35mm), 3/8in(9.53mm), 1/2in(12.7mm) Length: 72mm, 65mm, 65mm Quantity: 3pcs Weight: Approx. 99g Package Included: 3 *Extension Bars