The Orbea Range Extender is an auxiliary battery for ebikemotion X35 systems, and allows you to enhance your ride by going farther than ever. This new Orbea Gain charger makes bigger challenges and longer adventures possible, providing nearly 2 hours of additional boost at maximum power assist - something unheard of in the industry. When attached to Gain, the external device charges the bike's main internal battery, which has current capacity of 248W / h, and adds an additional 208W / h to the Ebikemotion X35 systems. This brings the total battery capacity to 450W / h, giving a 70% boost to the internal battery's charge. The Orbea E-Bike Range Extender is compatible with Gain F, Gain M and Gain D models from 2018 and newer, and Optima E models from 2019. It mounts on the saddle tube and diagonal tube, respectively. The external charger is NOT compatible with the eMX24 model. Orbea E-Bike Range Extender Features CAPACITY: 208.8w/h VOLTAGE: 36V DOWNLOAD RATIO: 1.9A WEIGHT: 1645gr (With specific bottle cage) COLOUR: Black anodised LOADING PORT: IWOC ONE BUTTON OF IGNITION AND DISPLAY OF LOAD. INCLUDES: Battery, bottle cage, rubber band, screws and mounting washers Before installation and use, consult the user manual included with the external charger.