REQUIRES MyKronoz ZeFit² or ZeFit² Pulse TO USE THIS APP. Compatible with select Android 4. 3 devices that support Bluetooth 4. 0 ble. Wear ZeFit2 and Get the App to stay fit and connected to your phone 24/7. ZeFit2 is a stylish connected wristband with touchscreen that tracks your daily activity and sleep quality. When synced to a smartphone via Bluetooth 4.