These Long-Lok® Pin-Style Spring Plungers with Slotted Sockets have bodies, pins & springs made from steel or stainless steel. They feature the Long-Lok® Thread System for securing the plunger in any position within the threaded hole. Long-Lok® Clockwise Insertion into a tapped hole expands the Long-Lok® System in the opposite direction, increasing resistance and therefore the amount of torque required for loosening.