Position: Mid drive motor. PAS sensor: Speed?? sensor. Reduction ratio: 1:21.9. 1 Mid Drive Motor. 1 Pair Brake Lever or Brake sensor. 1 Pair 44T Chainwheel (Default). 1 Set Thumb Throttle. 1 Set Speed Sensor. 1 4 to 1 Cable. 1 Wrench Tool (Free). Universal fit for most bikes. The adaptable BAFANG mid-motor kit integrates seamlessly with bottom brackets with a length of 68-73 mm and an inner diameter of 33.5-36 mm and complies with JIS standards. Note: 73 mm bolts are not included.