This is the ZeWatch4, a smartwatch band and health tracker from Swiss company Mycronoz. It's compatible with iOS 8+ and Android 4.3+. The iPhone app can be downloaded from the App Store, but the Android app has been removed from the Google Play Store. You can search for "zewatch4 apk" to download it. The manual can also be downloaded from the internet (Japanese version available). It has a built-in microphone and speaker, allowing for calls. Charging is done via a built-in USB connector on the end of the strap, using the included USB extension cable. *I haven't used the health tracker function at all, so I don't know the details.* *The notification function has issues with Japanese display, and I only used it for calls.*