Hi all,I'm the product manager for the OnePlus 5T. I'd like to talk about some of our decisions for this device. Specifically, how we came to combine the 18:9 Screen, Fingerprint Scanner on the back, and Face Unlock. With every product decision at OnePlus, we look at how features will affect other components, and how these additions will impact the overall user experience.For the OnePlus 5T, we used an 18:9 Full Optic AMOLED display. We took our time on this decision. We needed to get the screen right before adding it to the OnePlus flagship experience. The benefit of going from a 16:9 to an 18:9 aspect ratio is significant. User viewing experience for games and movies would be more immersive. There would be a 12.5% percent increase in screen area and reduce distractions on the front. We could have increased the size of the phone or gone bezel-less on the front, but we wanted to keep the same form factor that had worked well with the OnePlus 5. So, we moved the finger print scanner to the back. In past flagships, we felt strongly about keeping the fingerprint scanner on the front. This placement was intuitive to our users. You could unlock your device rapidly and easily, without picking it up from a table. But then, we improved our facial recognition technology enough to provide an interesting solution to improve user experience: double tap and unlock with a face scan.The fingerprint scanner on OnePlus devices is well known for its speed and accuracy. On the OnePlus 5, we clocked fingerprint scanner unlocking speeds at 0.2 seconds. Face Unlock would have to be impressively fast and accurate. Using our best practices from our fingerprint scanner development, we optimized the speed of Face Unlock through repetitions of testing. We kept adjusting until we whittled the total process time to 0.4 seconds in our tests. The fastest time we clocked for the recognition scan was 0.07 seconds. Face Unlock on the OnePlus 5T is now one of the fastest available on the market.For Face Unlock, we used an algorithm that relies on over 100 facial identifiers to detect your face. We tested it through all the scenarios we could think of: facial expression, lighting, accessories, makeup, hairstyle. We tested with different photos and held them at different angles. By release date, Face Unlock on the OnePlus 5T has a 99% success rate from eye and nose area scanning. It works whether you are wearing glasses or a hat. Face Unlock won't work while you are sleeping. That said, facial recognition technology on any device is not as impenetrable as fingerprint scanning. There are workarounds. But we’ve make some tweaks to ensure to make getting past the facial recognition algorithm is difficult, tedious, and time consuming. One of these is a passcode verification process, which kicks in if the scan mismatches repeatedly. We’ve also reserved Face Unlock for device unlocking, relying on fingerprint scanner for other security operations.The processes described above are only a partial look at the copious amounts of testing we do for each flagship release. We bring each iteration as close to perfection as possible, taking into account past UX findings. We wanted to give you a bigger screen and more immersive experience, but without compromising what we believe needs to be a fluid experience. That's why we worked on Face Unlock. If you have any thoughts on our decisions on screen and scanning technologies, we’d appreciate the chance to hear them.