Spin-Lock Rescue / Retrieval System, Locking Pulley for Combination Raise / Lower System The Spin-Lock Rescue system is a pre-rigged 4:1 Hauling system that utilizes a unique pulley with sheaves that rotate in only one direction. When properly rigged, this system works as an efficient 4:1 mechanical advantage pulley system that also provides friction to control the load when in lowering mode. The special sheave is mounted on a unique one-way bearing that allows the user to easily control a rescue load. Also, included is a Handled Ascender to control and anchor the system when at rest. The attached foot loop also aids the rescue in raising heavier loads.