The Petzl Macrograb is an ascender designed for permanent installation onto a rope. Macrograbs are usually installed on wire core fliplines, replacing a prusik hitch and giving you an adjustable lanyard. Installation is usually done by removing the cam with a wrench, installing the body on the rope or flipline and bolting the cam back on. This prevents accidental disengagement of this device. Connect to the rope grab with a certified carabiner. The steel cable acts as a spring to keep the cam tight on the rope. The body is made of lightweight anodized aluminum. Individually tested and CE approved. Fits most 1/2" to 3/4" ropes, but 5/8" is this devices sweet spot.