Anti-Radiation Earphone 3.5mm Air Acoustic Tube Earpiece Stereo Earphone with Microphone for Smart Mobile Phone

The last few inches carry sound, not current.

In a conventional earbud, the speaker sits inside your ear and the wire carrying the electrical signal runs all the way up to it. In an air tube design the speaker is moved down the cable, away from your head, and the final stretch is a hollow tube — sound travels the last few inches as air pressure, the way a stethoscope works.

That is the entire principle, and it is a straightforward mechanical one. There is no electronics and no wiring in the section that sits against your ear.