Function description of magnetic control car instrument, spinning bike instrument: 1. TIME: Press the MODE button to display the time. This value represents the total time from the start of the movement to the end. 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 total distance from the start to the end of the movement. 4. CALORIE: Press the MODE button to display the calories. This value represents the total energy burned from the start to the end. Works for HeadPhone-Look Cables]Both speedometer & 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 jack" look connection tips. E.g. many bike models by Sunny, PooBoo, L-Now, Snode, Exerpeutic, Pleny, Yosuda, Ativafit, Faafuu - 95% of Amazon brands as well as domestic brands [Heart Rate Monitoring Feature]that works with bikes with pulse sensors (usually 2 x metal pieces on handle bars). 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 * Monitor Speedometer W/ Heart Rate Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.