The Capri Tools Impact Universal Joint helps you reach fasteners in tight corners and spaces with power tools. Ball spring design that distributes torque evenly and works in a smooth 360 degree rotation. It features spring-loaded detent balls that securely hold sockets in place. We use premium Chrome Molybdenum steel tempered with our proprietary heat treatment process to make these impact universal joint adapters. They are durable and specifically made to withstand high torque from power tools. It is expertly coated with manganese phosphate, the preferred coating in military and aerospace, which offers superior protection and corrosion resistance compared to black oxide coating on other impact sockets. 3/8 in. drive.