Made of 7075 aerospace aluminum material which have high tensile force, it is stable and safer. The design of blocking teeth, the function is to jam the rope, and play the effect of grabbing the rope to prevent falling when the human body is tilted without weight. Quality-manufactured pulley for mountaineering, caving, exploring, tower work, rock climbing, mountaineering, exploring, rappelling, aerial work. Not easy to slide when hanging, more uniform force to use more smoothly. Suitable for diameter 9-13mm Rope.