The Beal Jammy is a sewn Prusik Loop made from 5.5mm cord with an aramid core and polyamide sheath. It can be used with either single or half ropes.

 

It is ideal for making a Prusik knot for increased safety and control during an abseil and also to create a progress capture for hauling/crevasse rescue. The sling works well either with the standard Prusik where the cord is wound round the rope several times before one end is poked through the other and clipped to a karabiner, or the French Prusik where both ends are clipped to the karabiner. The former is less likely to slip but more likely to jam.