This is the Qualisports Replacement 48V BATTERY CHARGER for the Dolphin 48V Electric Bike, Beluga STD/PLUS Electric Bike. Compatibility: Dolphin Beluga STD/PLUS Note on charger voltage: For the 36V battery, when fully charged, the voltage reaches 42V. For the 48V battery, when fully charged, the voltage reaches 54.6V. Product Specifications: Size: 7.09 * 3.54 * 1.77