Petzl Shunt 

Used below the rappel device, the SHUNT works as a rappel back-up and replaces friction hitches like the Prusik. Works on single and half ropes.

• Easy to install on the rope
• Smooth clamping surfaces won’t damage rope
• May be used to ascend single or doubled rope
• Rope compatibility: single ropes 10-11 mm or doubled ropes 8-11 mm