Ascender (climbing)

A pair of left and right handed ascenders (the left rigged to a rope)

An ascender is a device (usually mechanical) used for directly ascending, or for facilitating protection, with a fixed rope when climbing on steep mountain terrain. A form introduced in the 1950s became so popular it began the term "Jumar" for the device, and the verb "to jumar" to describe its use in ascending.

Ascenders can also be used as a braking component within a rope-hauling system, often used in rescue situations.