Universal Key Extension Tool. Designed to loosen and unlock stuck bolts with the ability to be used with any wrench so you can exert greater force on itself. Equipped with both a 1/2 square to be able to adapt a classic sliding T or 1/2 ratchet and a 21 mm hexagon, to be able to extend and exert force with a fixed star wrench on the closed or open side. Convenient and practical for use in any situation.