Camp Dryad Pro Rope PulleyCamp Dryad Pro Rope Pulley Compact double pulley for block and tackle systems. Main attachment point accommodates two carabiners and the becket features a bottom attachment point for linking components in a block and tackle system. For use with ropes up to 13 mm. Prusik minding, the self locking knot can be installed on both sides of both wheels. Sealed ball bearings for high efficiency and intensive use at high speed. Efficiency: 92%. Aluminum alloy