Ascender (climbing)

[2] 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.

[6] A popular example of the ascender is the jumar, named for its inventors Adolph Jüsi and Walter Marti and the Swiss firm Jümar Pangit they created to manufacture it, beginning in 1958.

In his 1978 memoir Life Is Meeting, John Hunt, leader of the 1953 British Mount Everest expedition, credits the jumar with enabling climbers "to climb at alpine standards even at high altitudes".

The principal disadvantages of ascenders relative to the "prusiks"[9][2]: 46–48  are weight, complexity, and possibility of failure due to coming off a rope or mechanical issue with the device.

Certain specialty forms of ascender - but not all - are capable of taking a dynamic load (as in preventing a fall), whereas the friction knot/Prusik combination may abrade the synthetic sheath of the climbing rope or sling and fuse under such extreme forces.

A pair of left and right handed ascenders (the left rigged to a rope)
Ascenders in use on a single rope on a steep mountain slope, offering the two climbers both security plus an additional aid to their upward ascent. [ 1 ] Note that they are not roped together, but are climbing independently of one another.
Historic Jumar rope ascender (ca 1975)
Historic Jumar rope ascender (ca 1975)
Using ascenders in to jumar up a fixed rope .