The Powerfly 4 625 takes our most affordable electric mountain bike, and gives it a boost with a longer-range 625 watt-hour battery. Of course, you still get our user-friendly Removable Integrated Battery (RIB) system that’s super easy to remove and reinstall, plus all the other parts that make Powerfly 4 your ideal entry into the joys of riding a pedal-assist bike on or off road.