Garage Door Chain Hoist has a 4:1 reduction drive ratio. 4:1 reduction Includes sprocket, 22" of #41 roller chain, 26' of hand chain, 1 chain keeper, 2 shaft collars, 1 wall bracket and a 1/4" key No cable jumping, jackshaft mounting (only applicable to 1-inch solid shaftinstallation). Chain Hoist can be easily slid onto the shaft forinstallation, and users can operate it without the need for professional skills. Suitable for commercial garages, residential garages, industrial garages, andwarehouses (additional chains might be required for doors over 14 feet or for verticalift doors or high lift doors).