Features: Bluetooth synchronize phone APP, recording currant riding data. Record data of the line, time and transmit the speed and pedal speed and etc. IP67 waterproof grade, you can enjoy your riding with it even in rainy days. To make your riding trip safer and funny. With bluetooth and ANT+ function. Description: Round shaped design, exquisite workmanship, fine appearance. Easily attach to your bike. Made of high quality plastic material, durable and long use life. Specifications: Material: plastic Color: black Size:21*21*8mm Battery model: CR1632 Function: waterproof Battery capacity:120mAh Work time: 90hours Voltage:3V Phone Requirement: Support Bluetooth 4.0 Package included: 1 x Sensor 2 x Magnet 1 x Assemble Accessories Set Notes 1. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2. Due to personal measurement technique is different, there may be 1-3 mm error of the physical.Thank you