Gibbs Ascenders are commonly used by rescue teams as a substitute for prusik cord brake in rope rigging systems. The ascender is spring-loaded, so it will support its own weight when there is no load on the cam. The shell bottom is rounded, improving its holding power by increasing the amount of surface area gripping the rope. A tough polyurethane coating on the cam helps provide a solid grip at normal loads and assures controlled sliding at loads over 2,000 lbs. Designed to work even in icy and muddy conditions. This stainless steel, 1/2" diameter Gibbs Ascender 5,400 lbs. of tensile strength. Designed to minimize damage to your expensive ropes. Works well under the most adverse conditions, even on muddy or iced ropes.