Construction: Geared Motor Nominal Voltage: 52V Efficiency: >80% PAS SENSOR: Speed sensor Shaft Standard: JIS. Gear sensor Function:Yes. Reduction Ratio: 1:21.9 Noise. Packing List : 1x Mid Drive Motor 1x Display (If you order together) 1Pair brake lever or brake sensor. 1x Headlight 1x Crank 1x 46T Chainwheel 1x Thumb Throttle 1x Speed Sensor 1x 1 to 4 Cable 1x Accessories 1x User Manual 1x Wrench tool. Compatible with bottom brackets of 68-73mm, and internal diameters of 33.5-36mm. Ideal for mountain, road, and commuter bikes. Note: Not suitable for carbon fiber frames or bikes with coaster brakes.