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The main issue with any Bluetooth device, especially ones that are right up next to your brain is that they have cell destroying frequencies that harm you. Talking on you phone while holding it to your ear, being close to your WiFi router at home, sleeping with your phone on next to you on your night stand are all examples of cell destroying behavior that should be avoided.

The ones I had always had this issue where using the microphone makes one of the pieces to vibrate in a way that is extremely uncomfortable.

Also walking feels like having a synthetic drum machine.

All those problems happen in sound isolation mode.