Features: - Pure mechanical bike computer has accurate data. - It works for 26/27.5/28/29 inch bikes only, be sure to check your bike size before you buy it. - The must instrument you should need for your bike journey, and you'll find it useful. Specifications: Material: Aluminum Alloy Size: Approx. 12*8*5.5cm/4.72*3.15*2.16in Package included: 1 x Cycling Odometer Notes: 1. Manual measuring, please allow 1 ~ 3mm error, thank you. 2. 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 picture.