The Capri Tools Locking Universal Joint Set helps you reach fasteners in tight corners and spaces. It features spring-loaded detent balls that securely hold sockets in place, and a pull down ring that effortlessly releases the sockets letting you switch between sockets on the fly. Constructed of premium Chrome Vanadium steel tempered with our proprietary heat treatment process to withstand more torque. Each item underwent careful polishing and protective plating process to achieve our own SmartKrome finish. Chrome Vanadium tools are designed for hand tools and should be used with hand (non-powered) tools only. For applications using power tools, use Capri Tools impact sockets, adapters and extensions. 3-piece set: 1/4 in. drive, 3/8 in. drive, and 1/2 in. drive universal joints.