Bicycle/Bike Computer : Wireless Speedometer (Discontinued by Manufacturer) Royal BC300 Wireless Bicycle Computer w/13 Functions General Features: Compact sport design Wireless mounting shoe Easily attaches and detaches with mounting shoe Easy to install Magnetic sensor attaches to bicycle spoke Supports miles and kilometers Powered by 3V CR2032 battery (installed) Functions: Speedometer (0-99.9 Km/hr or M/hr) Tripmeter (999.99 Km or M)