Featuresr it is a professional product for exercise enthusiastsr by installing this product we can always get a precise cadence data because it is mounted on the cranks and spokes of bikesr real time data transmission via bluetooth to apps on smart phones provides accurate and professional cycling data for better cycling motion analysisr it works for iphone 4s ipad ipod newer versions and for androids 43 and abover powered up by a cr2032 lithium battery which is included