Specifications:It is made of premium quality ABS material which makes it very safe and durable.Meanwhile, this odometer is waterproof so it is very convenient for you to use it in rainy days.Furthermore, due to its special backlight feature, you can use it both at day and night.Also, it is very easy to install and is suitable for most of the bicycle models.What's more, it is multifunctional so you can use it as a stopwatch timer.Therefore, it would absolutely be a perfect miles counting tool for your bike. Item Name: Bicycle Speedometer Material: ABS, Electronic Components Features: Waterproof, Backlight Odometer, Stopwatch Timer Size: 5.7cm x 4.1cm x 2cm/2.24" x 1.61" x 0.79" (Approx.) Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes:1 x Bicycle Speedometer, 1 x Bicycle Speedometer Base Sensor, 1 x Magnet, 6 x Ties, 1 x User Manual, 1 x CR2032 Button Battery for Bicycle Speedometer (Included)