This newest version of the Rope Wrench comes from ISC and is refined with rounded edges, smooth bolts and pins, and the high-end construction you’d expect from ISC. The ISC Rope Wrench is a unique tool for unique climbing arborists. Installed with a stiff tether above a traditional hitch of your choice, the two 90-degree “bends” add just enough friction to the system for a stationary line system to act like a moving or doubled line system.