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 energy burned during the workout. Works with 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 needed 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 home and commercial fitness bikes. Heart rate monitoring feature works with bikes equipped with pulse sensors, typically two metal contact points on the handlebars. Rewiring may be required for certain models. 2 x AAA batteries are required (not included). Product dimensions: 108 x 163 mm LCD size: 48 x 23 mm Color: White Material: Plastic Package Contents: 1 x Monitor Speedometer with Heart Rate Function Note: Light and screen display differences may cause slight color variation between the product image and the actual item. Measurement error allowance is +/- 1-3 cm.