Made of high quality alloy steel (chrome-molybdenum). Designed for outer cap nuts on budd-style truck wheels. "Controlled depth" hex end to help prevent contact with the wheel. The socket is deep style to eliminate contact with the inner cap nut. Lifetime Warranty Grey Pneumatic sockets are designed for professional tool users. This socket features our "high torque" drive. This limits the amount of wear on the corners of the fastener and the socket. It also improves the strength of the socket, transfers increased torque to the fastener and allows easier access to tight areas.