Treks Removable Integrated Battery System looks great and is user-friendly: it is completely integrated into the frame, providing excellent protection, easy to remove without tools, and even has space for a water bottle holder. This bike expands horizons: the premium Bosch system is perfect for daily commuting, leisure rides, and great times on the trail. The Purion controller features a Walk Assist function and an intelligent eMTB mode that automatically delivers the required power depending on the terrain. Thanks to the external charging port, you can easily and conveniently charge the battery in the frame or when removed.