COMPATIBILITY - CAN THE HEADPHONES BE USED WITH SMARTPHONE/SPORTS WATCH/MAC/PC ETC.?

Yes – as a general rule, all MIIEGO® products can connect to smartphones, watches, computers and other devices of any brand, provided that the device in question is equipped with Bluetooth. Your phone/device must support A2DP (Advanced Audio Distribution Profile) to be able to play music, which almost all newer smartphones do.