The Bip is equipped with a 1.28-inch transflective color display, covered with a 2.5D layer of Gorilla Glass 3. While it does have its drawbacks, mainly in resolution and color pallet, this display is incredibly battery efficient and also benefits in terms of legibility in sunlight. It plays a major role in achieving the gadget's advertised 45-day battery life - an amazingly frugal use of its 190 mAh battery.
That number is achievable when using the Bip with an always on time display and running sleep and motion monitoring in the background.
However, The Bip is also equipped with a PPG heart rate sensor, triaxial acceleration sensor, geomagnetic sensor, barometric pressure sensor and last but not least, GPS + GLONASS. Taking it out on the track and blasting all the sensors on continuously brings down the battery life to around 22 hours - still among the best out there. This, along with an IP68 rating make the Bip a great workout companion. Running, walking and cycling tracking are all supported out of the box. Just don't expect to swim laps in the pool with it.
The Bip runs on a custom Xiaomi-made OS, with no support for additional apps. Still it is enjoying a vibrant third-party developer scene and customization with additional watch faces and custom notifications is already possible. On the official side of things, Amazfit provides the Mi Fit companion application for Android 4.4 and iOS 8 or newer for Bluetooth connection, data sync and notifications on the Bip.