The Withings ActivitŽ Pop is a stylish activity tracker with Bluetooth capability and a companion app to let you know your progress. The ActivitŽ Pop is the sportier, more affordable relative of the ActivitŽ. The ActivitŽ Pop tracks running, sleeping, and swimming metrics. The battery on the device lasts up to 8 months before needing replacement. The ActiviteŽ Pop is currently compatible with iOS devices, specifically iPhone 4S and above.