A guitar amp.
Specifically a lunchbox amp.
More specifically, the Orange Micro Dark.
It's a 20W hybrid amp, containing a single 12AX7 vacuum tube in the preamp, and having a solid state power section.
One channel, able to go from "cleans" to lots of distortion, has a volume, tone, and gain knob.
Has a headphone jack, on top of an effects loop, believe it or not, and can take any 8Ω or 16Ω speaker cabinet.
Mostly, I got it for the sound, novelty, but primarily for the reason to practice guitar silently with headphones. My main amp, a Mesa Dual Rectifier, is just a 100W, all tube beast that doesn't know what quiet is.
Best of all, one of the most affordable, and best sounding amps in its price range, at a comfy $180.
As a point of reference, my Mesa Dual Rectifier, costed me around $2100.