This power-assist system for manual wheelchairs is designed to be intuitive to use: Push to go, brake to stop. To go faster, just push faster. Set the speed of the SmartDrive via the speed of your push. The battery fits under the seat, while the SmartDrive motor attaches to a hitch on the back of the wheelchair. The unit, which weighs 19 lbs., fits onto most manual wheelchairs, including folding ones. It has a 10-mile range and features indoor and outdoor modes.