TLDR: This pocket-sized disk serves up incredible audio via its bone-conduction technology, turning almost any surface into a beefy amplifier.

Mobile devices like smartphones and tablets are fine when you’re plugged in with earbuds. But few of those devices are created with powerful (and prohibitively expensive) external speakers to listen easily without the use of headphones. Even at top volume, it might be enough to satisfy anyone within a 5-foot radius as a temporary listen…but it certainly doesn’t deliver any serious audio fidelity or scope.

Rather than toting around big portable Bluetooth speakers to handle those types of listening situations, a nimble little trooper like the HumBird Speaker ($26.95, 39 percent off, from TNW Deals) can be a far less intrusive, and far more impactful alternative.

Befitting its tiny namesake, the HumBird is the world’s smallest and most versatile bone conduction speaker. The small metal disk barely measures over 1.5 inches, but it’s sound is ridiculously mighty thanks to its bone conduction tech. Rather than packing a hefty collection of woofers and tweeters, the HumBird actually lets you use the natural acoustics of virtually any hollow object around you to get major booming sound out of this little powerhouse.

Just connect the speaker to your device via Bluetooth, then place the Humbird on almost any surface, from a wooden table to a plastic storage crate to even something truly unusual like a cardboard box or a guitar or a basketball. The HumBird will then use its bone conduction powers to turn those objects into speakers, naturally amplifying your music, podcasts, or even phone conversations to up to 115dB. That’s almost 5 times louder than an average device speaker.

The speaker even picks up some of the natural properties of the object it’s using to amplify. The HumBird on wood offers a thick, natural sound, while glass creates a clear, resonant audioscape. Meanwhile, paper serves up a sound that isn’t unlike what you hear from a vintage vinyl record. Different materials meet different vibrations at different frequencies, allowing users to craft their own unique audio experience.

The device can even connect to a second HumBird speaker for a stereo surround sound effect, while this battery can supply up to 3 hours of continuous play.

The HumBird Bone-Conducting Speaker normally retails for $44, but as part of this offer, it’s on sale now for almost 40 percent off, down to just $26.95 while this offer lasts. It available in silver, red, and black editions, or in two-packs with silver, red, and black tandems on sale for only $44.95.

Prices are subject to change