The Trek Rail 5 SX 625 is an electric mountain bike. It has a new Bosch drive system to help you over the trickiest terrain. The frame is made form lightweight aluminium which has the 500Wh battery encased in it with a Bosch performance line CX 250 W motor which can get up to 25 km/h. The integrated battery system looks good and is use friendly but it can be easily removed without tools. It has an external charging port so it can be charged on or off the bike. It is small, quiet and efficient and has an eMTB mode which will adjust the amount of assist it gives you depending on the terrain.