For the XO-ET31 I have to say the following. They do not turn off (not disconnect) when you take them out of your ear, but they continue to play music. They do not have a battery indicator for their case, compared to others. You cannot adjust the volume from them, but only from the mobile phone. The touch sensor, located on the vertical cylinder of the earphone, is quite sensitive, resulting in the slightest accidental touch interrupting the sound (call or music). The distance you can move away from the mobile phone without the connection being interrupted is up to five (5) meters in a straight line, without obstacles. Their charging time exceeds three (3) hours, without knowing exactly how much. Also, there is no indication of their charging on the base, so you can understand when they are fully charged. The sound in music playback is quite good. Their microphone is quite clear to the interlocutor. Fully charged, they lasted for four hours for music playback at maximum volume.
12/12/23. I come back to say that, while the mobile phone was in the inside pocket of my jacket at chest height, during walking in an open space and using mobile data, the radio sound I had put on would stop for seconds.
03/05/24. I come back to say that, after using them for six months for only one hour in a 24-hour period, their batteries gave out and no longer charge.