Sunding SD-558A Wired Waterproof Bike Speedometer Backlight Odometer Stopwatch 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 light-controlled smart backlight feature you can use it both at day and night. Additionally it has constant backlight and low battery reminder functions which makes it very secure for you to use. Also it is very easy to install and is suitable for most of the bicycle models. Therefore it would absolutely be a perfect tool for your bike. Item Name: Bicycle Speedometer Material: ABS Electronic Components Features: Waterproof Backlight Odometer Low Battery Reminder Size: 9cm x 4cm x 1.5cm/3.54" x 1.57" x 0.59" (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. Certification:CE Origin:CN(Origin) Stopwatch and Accessories:Wired Stopwatch