By constructing the Lifeguard without the internal spring, the Safeguard is a great tool for rescue and rigging work. It will lock onto the rope with very little force giving you the confidence that once the position of the rope is set the device will not creep or slide. For rescue/rigging use: 8.1mm to 11mm rope diameter For climbing use: 8.9mm to 11mm rope diameter Hot Forged Aluminum and Stainless Steel construction Individually tested