The list of useful things that Mason jars can hold seems to be never ending, something that's proven with the mason jar speakers by Trash Amps.
The design of the Mason jar lets your tunes sound projected and amplified, like how you’d want your music to sound like. The small jar is easily transportable and plugs into any device, and is even well suited for electronic instruments. It automatically detects what sort of device is plugged in, and self-adjusts accordingly. The Mason jar speakers takes portable technology back to basics, with its minimalistic and environmentally friendly materials like glass, wood and metal. Portable and simple, you'll be able to jam on for hours.