The twion power add-on wheels by alber were designed with maximum user independence in mind. Equipped with dynamic electric motors, lithium ion batteries and leading edge digital electronics, the twion provides the user with up to 6km/h of power assist with every propelling movement. A handrim sensor calculates the right amount of assist needed. Weighing in at only 13 lbs.* per wheel and a quick release mounting system. The twion is the perfect, flexible and efficient solution for users seeking high agility and simple handling. FREE twion Mobility App download for access to digital services including the quickstart guide, diagnostic checklist and provider locator. Add the Mobility Plus Package <> to your wheel set to unlock additional features on your Mobility App and enjoy more features such as: additional power assist up to a total of 10 km/h, wheel information, additional drive modes, odometer, standby mode, TOUR mode, CRUISE mode, sound profiles and the world's first BlueDrive** controller: an option that allows you to drivel your wheelchair remotely using your smartphone. *Includes battery.