In two Xiaomi phones that I have used, while the sound is quite loud when listening to music or watching Netflix, it is very low during phone calls, resulting in me not being able to hear what they are saying even if I push them deep into my ear. I can hear them better on Viber and Messenger. It doesn't have much bass. Generally, when I speak normally, the callers hear me a bit low, and if I speak softly, they can't hear me. Also, I don't know what's going on with the noise cancellation. Sometimes they say they can hear everything from my surroundings louder than my voice (e.g. the radio), and other times they say they can hear me just fine under the same conditions. They don't fit well in my ears (my own problem as no non-in-ear headphones fit me), so I got silicone hooks for AirPods and they fit fine and block external sounds by 50%. Overall, they do their job, especially for the price they cost, but don't expect above average results. To connect them, after taking them out of the case and they both start blinking, first one connects to the other, so one stops blinking, and then if you turn on Bluetooth on your phone, the free one connects to it. If you already have Bluetooth on your phone turned on and you take them out of the case, sometimes they get confused and one never connects until you repeat the process with Bluetooth turned off on your phone. They charge with an iPhone-type cable included in the package, not with a micro USB or USB-C.