Function of magnetic control car instrument, spinning bike instrument: 1. TIME: Press the MODE button to display the time. This value represents the time from the of the movement to . 2. SPEED: Press the MODE key to display the speed. This value represents the speed of the current movement. 3. DISTANCE: Press the MODE key to display the distance. This value represents the distance from the to of the movement. 4. CALORIE: Press the MODE button to display the calories. This value represents the energy burned from the to . Works for HeadPhone-Look Cables]Both speedometer and pulse trakcing connection are through 3.5 mm female jacks on the back the monitor - adapters (NOT INCLUDED) might be needed if the device also happen to have FEMALE jacks (rare cases). [Compatible with Most Indoor Exercise Bikes] - for Stationary Bikes with "head phone " look connection tips. E.g. many bike models by Sunny, , L-Now, , , Pleny, , , Faafuu - 95 percent of Amazon as as domestic [Heart Rate Monitoring Feature]that works with bikes with pulse sensors (usually 2 x metal pieces on handle ). Re-wiring MIGHT be required for some perticular models. [2 x AAA Batteries Not Included - Required]Batteries are NOT included. Product size: 108x163mm LCD size: 48x23mm Colour: white Material: plastic Package Contents: 1 x Monitor Speedometer W or Heart Rate Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is 1-3cm.