Function description 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 during the workout. 3. DISTANCE: Press the MODE button to display the distance. This value represents the total distance covered during the workout. 4. CALORIE: Press the MODE button to display the calories. This value represents the estimated energy burned during the workout. Works with Headphone-Look Cables: Both speedometer and pulse tracking connections are through 3.5 mm female jacks on the back of the monitor. Adapters (NOT INCLUDED) might be needed if the device has female jacks (rare cases). Compatible with Most Indoor Exercise Bikes: Designed for stationary bikes with "headphone" style connection ports. Fits many models from brands such as Sunny, L-Now, Pleny, Faafuu, and others. Compatible with approximately 95% of home and commercial indoor bikes. Heart Rate Monitoring Feature: Works with bikes equipped with built-in pulse sensors (typically two metal contact points on the handlebars). Re-wiring might be required for certain models. 2 x AAA Batteries Not Included - Required: Batteries are not included. Product size: 108x163mm LCD size: 48x23mm Color: White Material: Plastic Package Contents: 1 * Monitor Speedometer with Heart Rate Function Note: Light and screen display differences may cause slight color variation between the image and the actual item. Measurement allows an error of +/- 1-3cm.