An ascender is a device (usually mechanical) used for directly ascending a rope, or for facilitating protection with a fixed rope when climbing on very steep mountain terrain. Ascenders can also be used as a braking component within a rope hauling system, often used in rescue situations. Use Ascenders are usually used in pairs, and offer similar functionality to friction knots, but are faster, safer and easier to use, albeit still with consequences in weight and in security (as ascenders can, even with a locking carabiner, come off the rope, and fail by shredding the rope at high loads, rather than slipping and fusing as with friction knots). A mechanical ascender employs a cam which allows the device to slide freely in the intended direction of movement, but provide a firm grip on the rope when pulled in the opposite direction. To prevent an ascender from accidentally coming off the rope, a locking mechanism or trigger is deployed. The ascender is first attached to the climber's harness by a piece of webbing or sling, and then is clipped onto the rope and locked on. Ascenders are usually used in pairs, so that one is free to be slid up the rope whilst the other bears the weight of the climber. The ascender which has just been slid upwards is then made to take the climbers load, so locking him to the rope, and freeing the other one so it, too, can then be slid upwards too. The process is then repeated to ascend the rope. For climbing on with a fixed rope attached for security (for example, to snow anchors on a steep slope) only one ascender is used, keeping the other hand free for holding an ice axe. Ascenders are not typically used on free climbing routes, where a climber uses his or her hands and feet on the rock, climbing the features, edges, cracks, and pockets that the route provides without artificial aids. Instead, they are more likely to be used in aid climbing. Jumar One such ascender device is a jumar, named for its manufacturer Jümar Pangit, a company in turn named after jumar inventors Adolph Jüsi and Walter Marti. From the name of the Swiss firm Jümar Pangit which manufactured it, in turn from the surnames of Adolf Jüsy and Walter Marti. Jusi was studying eagles for the Swiss Government, and needed an ascender. Marti developed