Petzl Shunt Ascender

Petzl Shunt ascender.

Actually, as a lever cam device it can act as both a jammer and a safeguarder of abseiling. Basically it is useful if you are likely to encounter:

1. Very muddy ropes, because the grip is due to weight being placed on the Shunt, which the device transmits to the rope - unlike most sprung cam jammers, which rely primarily on the teeth on the cam gripping the rope.

2. Icy ropes, for the reasons as above. In each case the Shunt is best used as a hand jammer.

3. A fixed rope which safeguards a ladder. One device can function to safeguard ascent and descent.

Probably not for everyday use, but a very handy resource to have available if you're digging or planning on meeting icy entrance pitches this winter!