RACK is an easy-to-use caving descender. It can be used with 9 to 13 mm diameter low stretch kernmantle ropes (on one rope strand) or with 8 to 11 mm low stretch kernmantle ropes (on two strands) to facilitate long descents over 80 meters. The brake bars are replaceable to prolong its useful lifetime.

• Simple to use:
  - Very easy to use; the bars engaged on the rope can be adjusted at any time to obtain the desired amount of friction
  - Compatible with 9 to 13 mm diameter low stretch kernmantle ropes
  
• Suited for long descents (over 80 meters):
  - Can be used on two rope strands, with 8 to 11 mm diameter low stretch kernmantle ropes
  - Good distribution of friction and heat helps preserve the rope
  - Does not twist the rope
  
• Lifespan of the device can be optimized by replacing the brake bars (D11300, D11250, and D11200)

See Petzl's Choosing your descender for caving for more information