A high-quality pulley is the heart of a good moving rope system. Using a pulley to tend your hitch frees you up for one-handed slack-tending. A pulley with multiple anchor holes streamlines your climbing system, and opens hauling and mechanical advantage uses. Some climbers install a high-efficiency ball-bearing pulley on the rope bridge of their harness. Using a pulley on the harness bridge reduces wear on the bridge, and lets the tie-in point traverse easily. Using pulleys throughout your system can reduce friction and improve efficiency.