Just in case the word "conduction" triggered the question about health risk: in this case it just means the sound is transferred by direct contact of the resonator on the speaker with your cheekbone (well, as direct as going through the skin can be). There's no electrical signal going into your body, just vibration moving through your skull directly to the inner ear, rather than via air into the air canal.

Music is actually pretty unsatisfying at any volume above background levels in an otherwise-quiet room, since any significant bass through the conduction 'phones actually makes them jump out of contact with your head, resulting in a buzz you can feel + hear. Calls, podcasts, YT videos, etc. all work great.