Function of magnetic control car instrument, spinning bike instrument: 1. TIME: Press the MODE button to display the time. This value represents the duration of the workout. 2. SPEED: Press the MODE button to display the speed. This value represents the current speed of movement. 3. DISTANCE: Press the MODE button to display the distance. This value represents the total distance traveled during the workout. 4. CALORIE: Press the MODE button to display the calories. This value represents the estimated energy burned during the workout. Compatible with devices that have headphone-style cables. Both speedometer and pulse tracking connections are through 3.5 mm female jacks on the back of the monitor. Adapters may be required if the device has female jacks (in rare cases). Compatible with most indoor exercise bikes, including stationary bikes with "headphone" style connection tips. Fits many models from brands such as Sunny, L-Now, Pleny, Faafuu, and others. Compatible with approximately 95% of commercial and home fitness bikes. Heart rate monitoring feature works with bikes equipped with pulse sensors, typically two metal contact points on the handlebars. Re-wiring may be necessary for certain models. Requires 2 x AAA batteries (not included). Product dimensions: 108x163mm LCD screen size: 48x23mm Color: White Material: Plastic Package Contents: 1 x Monitor Speedometer with Heart Rate Function Only the items listed above are included; other products are not included. Note: Lighting and display settings may cause slight variations in the color of the item as shown. Measurement error allowance is +/- 1-3 cm.