This ultra-compact ‘vibro-speaker' claims to turn any hard surface into an ‘effective and powerful' speaker. We feel duty bound to disagree with both those claims.
Connect an MP3 player via 3mm minijack and while, yes, the speaker does work – held in the air the tiny device makes a noise like a mosquito trapped in a jar, put it on a table and the midrange and bass appear – the noise it produces is almost not worth the effort.
At low volume the track is discernible if lightweight, but when turned up it's scratchy, and prone to vibrate as it attempts to generate bass.
It's an eye-catching theory but our ears weren't so happy with the idea in practice.