Description: 【Eco Friendly Mechanical Design】: This Bike Speedometer requires no battery, offering an environmentally friendly experience. It provides stable and reliable data record without the need for charging or battery replacement 【Accurate Real Time Tracking】: Keep track of your cycling distance with precision. This odometer ensures that every ride is accurately recorded, supporting your scientific training and helping you monitor your progress effectively 【Wide Compatibility with Various Bike Sizes】: Designed to fit a range of wheel sizes including 26", 27.5", 28", and 29", this Bike Computer Wired Speedometer is compatible with most mainstream mountain bikes and road bikes, ensuring versatility across different bike models 【Stable Installation for Larger Hub Gaps】: Specifically designed for bicycles with larger hub gaps, this odometer offers a more secure installation that remains stable during rides, minimizing the risk of misalignment or 【Construction for Diverse Riding Conditions】: Featuring a strong outer shell made from plastic, metal, and acrylic materials, this odometer is built to withstand tough conditions such as trail or commutes. Its dustproof and shock resistant design ensures longevity in various cycling environments Specification: Size: 8cmx6cmx5cm/3.15inchx2.36inchx1.97inch Material: Plastic, Metal, Acrylic Size Chart: It displays the total mileage and single mileage (the knob next to it can reset the single mileage) Electric vehicles cannot be installed and used Suitable for apertures within 1cm Package Includes: 1 Set Bike Computer Wired Speedometer Note: Please allow 1-3mm measuring deviation due to manual measurement. Due to the different monitor and light effect,the actual color of the item might be slightly different from the color showed on the pictures.Thank you!