ISC Phlotich Pulley

The ISC Phlotich pulley is a compact pulley from ISC for tree climbing setups, sized for tending a friction hitch or building a small mechanical advantage system. Its small size keeps the hitch close to the pulley and the bridge tidy.

Where a micro pulley fits

On a moving-rope system, a small pulley below the friction hitch lets the hitch be tended as you advance, so you climb with one hand free and the hitch stays clean. It also gives you a sheave for a quick 3:1 to tension a line or lift a light load.

ISC makes several compact pulleys, so check the markings if you are matching an existing setup. More options are in our micro pulleys section.

Pair it with a hitch cord that suits your climbing line, and set the hitch so it sits snugly against the pulley without jamming. A well-tuned setup tends smoothly and is less tiring over a full day of climbing.

Inspection and use

Before each climb, spin the sheave, look for cracks, burrs, or play at the axle, and make sure the side plates open and close as ISC intends. Clean sap and grit out of the sheave and keep it away from chemicals.

Use a locking carabiner, keep loads in line with the pulley, and stay within the rope range and rating on the side plate. Retire it after a hard drop. Life-support use must follow ANSI Z133, the manufacturer's instructions, and your training, and the gear should be inspected before every climb.