these are functional listening devices.
they have a 1/8 inch, and 1/4 inch jack that can be plugged into any headphone outlet, on any piece of musical equipment. you can listen to music when held up to the ear, as if you were talking on the phone. if you plug the jack into a microphone outlet, the bottom speaker becomes a microphone. you can talk into it, as if you were talking on the phone. i developed them to be used for djing, primarily. i hand-wired, assembled, and painted each phone; i also designed and built the display boxes. they were the focus of my show "blue days black nights" at Sweet Jane Vintage.