Technology keeps on shrinking, but HumBird (about £19) is perhaps pushing at the edge of the absurd. It’s a speaker, yet measures only 4cm across, and it weighs a piffling 35g. Plonk down one (or two if you want stereo) and HumBird will use bone conduction technology to customise your listening experience by transforming whatever object it rests on into an impromptu loudspeaker. You can use a table, your car’s dashboard, or even your head, ramping up the volume to something approximating five smartphone speakers blaring in unison. This doesn’t exactly scream audiophile bliss, but HumBird isn’t angling to replace your high-end sound system. For the outlay, it could be an amusing audio toy, though – and make the box it arrives in have some use beyond getting the thing to you in one piece.