little stretch, which is most useful for applications such as hauling and rappelling. Dynamic rope is used to belay climbers, and is designed to stretch under a heavy load to absorb the shock of a fallen climber. Dynamic ropes manufactured for climbing are tested by the UIAA. A test of "single" standard rope involves tying an 80 kg (176 pound) weight to the end of a length of rope. This weight is then dropped 5 meters (16½ feet) on 2.7 meters (9 feet) of rope, with the rope running over a rounded surface simulating that of a standard carabiner. This process is repeated until the rope breaks. For "double" ropes the weight is 55 kg, and for twin ropes two strands are used. In addition to the number of drops, the impact force is also measured. It is a common misunderstanding to think that the number of drop test falls (as conducted by the UIAA) is the number of real-life climbing falls a rope can sustain before it becomes unsafe. The drop test falls are of extreme severity and a real-life climbing fall will not often generate a comparable force. This adds a margin of safety for climbers who use such ropes as the ropes age. Rope care Kernmantle rope should be inspected before and after every use for any form of damage. "Boogers", which indicate internal damage to the kern, appear as tufts of white threads poking out from the mantle. Ropes that have been severely stressed have tapered sections which are visibly or palpably thinner due to crushed or parted (incomplete) core strands. Parted core strands no longer provide full strength to the rope, and (if not tightly braided) tend to withdraw from the damage with use, twisting & kinking toward the undamaged ends. Rope that has been abraded or cut on sharp edges should be examined closely by an experienced user, who may choose to cut the rope at that point, rather than risk it parting at that location. A rope can be cleaned by forming it into a chain sinnet to prevent excessive tangling and washing it in a front-loading clothes washing machine with soap flakes. Strong cleansers, including bleach and detergent should not be used on life-critical nylon components. Commercial rope cleaning devices are also available, but must be used carefully to avoid kinking (& weakening) the core strands. Typical specifications *Dynamic ropes are rated