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 movement. 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 movement. 4. CALORIE: Press the MODE button to display the calories. This value represents the energy burned during the activity. Compatible with devices using headphone-style cables. Both speedometer and pulse tracking connections are made through 3.5 mm female jacks on the back of the monitor. Adapters may be required if the device has female jacks (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. Suitable for approximately 95% of home and commercial fitness bikes. Heart rate monitoring feature works with bikes equipped with built-in pulse sensors, typically two metal contact points on the handlebars. Re-wiring may be necessary for certain specific models. Requires 2 x AAA batteries (not included). Product dimensions: 108 x 163 mm LCD screen size: 48 x 23 mm Color: White Material: Plastic Package Contents: 1 x Monitor Speedometer with Heart Rate Function Note: Lighting and display settings may cause slight variations in the color of the item shown in images compared to the actual product. Measurement error allowance is +/- 1-3 cm.