Vivo y66 is my first phone.I know about it very well.It is a very long life phone. I bought it one year ago. But it has never hang. It’s features is super. It can be done eight mb picture. And it’s network speed up to 10 mb/s .it’s front camera is 16 megapixel. Light sensor: Automatically detects ambient light and adjusts the brightness of the screen accordingly. Proximity sensor: When making phone calls, this sensor automatically detects to the distance between you and your phone, it will switch off your screen to avoid unintentional triggering of certain functions.The sensor is inactive in headset and headsfree mode.etc.