A dynamic rope is a specially constructed, somewhat elastic rope used primarily in rock climbing, ice climbing, and mountaineering. This elasticity, or stretch, is the property that makes the rope dynamic. Greater elasticity or stretch allows a dynamic rope to more slowly absorb the energy of a sudden load, such from arresting a climber's fall, by reducing the peak force on the rope and thus the probability of the rope's catastrophic failure. A kernmantle rope is the most common type of dynamic rope now used. Since 1945, nylon has, because of its superior durability and strength, replaced all natural materials in climbing rope.