PAFERS XSPIN Indoor Cycling Cadence/Speed Sensor, Black Innovative circular motion detection technology Installable on Indoor Cycle (Spin Bike), Elliptical, Fitness Bike, Bike with trainer Equipped with Bluetooth Smart (4.0) technology, the Xspin has long battery life - holds up to 600 hours of use) Two free training apps included, Cycle on Earth and Cycle Rush Compatible with iPhone 4s, 5s, 5c, iPad 3, 4 Mini, iPod Touch 5