Features: Featuring simple installation and disassembly, it is more convenient to use.The function of this pedal assist sensor is to help extend cycling mileage with good accuracy. Extend battery life and improve vehicle cruising range. Avoid damage to the battery due to high current discharge This product is perfectly suitable for bike, electric bicycle, etc. According to the speed of the turn of the foot to identify the power, pedal up in the process of riding is more lightweight and electricity saving. Specification Size:Diameter of outer ring 6.5cm, diameter of inner ring 1.5cm Package Include:1Pcs * E-bike Assist Sensor Note: 1. Due to the different monitor and lighting effect, the actual color of the item may be slightly different from the color shown on the pictures. 2. Please allow 1-3cm error due to manual measurement. (1 inch = 2.54 cm) Thanks for your support :) Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!