Impact Sockets Developed For Your Power Tools. Specially designed to resist the stresses from impact, or “Dynapact” tools. Their special steel and heat treatment ensure very high yield strength and wear resistance. All sockets and accessories feature a groove and side-hole to UNI ISO 2725. Locking is ensured by a through-pin and retaining ring (to be ordered separately). Never fit chrome-finished manual sockets to Impact tools.