27.5 MTB mid drive electric bicycle is strong with hidden battery style.all parts is good quality brand  parts .   1. frame use 27.5*2.3 MAXXIS with 6061 Aluminum alloy frame .    2. motor use 36v250w /48V350w/ 48v500w/48v1000w BAFANG mid drive motor.  3. battery  use 36v or 48v10.4 /14.5/16ah panasonic or samsung  lithium battery .    4. brake system  use tektro mechanical disc brake or tektro hydraulic disc brake.   5. front fork use Suntour or RST oil alloy suspention adjustable front fork. 6. display use bafang C10 or C18 color LCD Display     7.wellgo alloy pedal . 8. velo leather grip and saddle.     9.  promax  seat post and handlebar .   10. prowheel crank. 11.front &rear LED light.    12. KMC chain..   13 shimano altus 7 speed or Alivio 9 speed or deore 10 speed.