Page 627 - Bob Holtzman "The Field Guide to Knots How to Identify, Tie, and Untie Over 80 Essential Knots for Outdoor Pursuits"

4. Pull down on the second bight to lock the sling onto the main rope. The knot can be easily slid up or
down the main rope when it is unloaded.

Uses: climbing; moveable handholds or clip-on points on climbing rope
Pros: more secure than Prusik Knot

Cons: none known

Untying: Pull the second bight out of the first bight, then pull to unwind the

sling from the main rope.

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