FeaturesWorks for Headphone-Look CableSpeedometer and heart rate tracking connection is via 3.5mm jack on the back of the monitor - adapters (NOT INCLUDED) may be required if the device also has a HON jack (rare cases). Compatible with most indoor bikes - for exercise bikes with a \"headphone jack\", see connection advice. For example, many bike models from Sunny, PooBoo, L-Now, Snode, Exerpeutic, Pleny, Yosuda, Ativafit, Faafuu - 95% of Amazon brands as well as national brands Optional heart rate measurement function optional that works with bikes equipped with heart rate sensors (usually 2 metal parts on the handlebars). Some models may require a switch. 2 AAA batteries not included - Required battery NOT included. SpecificationModel: ZT-JP040 Counting range: 9999 (pcs) Input signal voltage: 1.5V(V) Specification: SM connector size: 147*124mm LCD screen size: 50*23mm Tips: Please allow 1-3cm measurement error. The photo color may be slightly different from the actual product due to the color display of different monitors. Product includes: 1x Speedometer.