Polk's Boom Bit ($30, £40) may not be the first wearable Bluetooth speaker, but it's one of the most ambitious attempts at creating a wearable Bluetooth speaker.
The size and shape of a cigarette lighter, the tiny, ruggedized Boom Bit (1.1 ounces or 32 grams) is water-resistant and has an integrated microphone so it doubles as a speakerphone. The built-in clip allows you to securely fasten the speaker to your clothing and it's ideally worn at around collar level, where it can sit not too far from your mouth and ears. There are volume controls on the speaker, which is good.
At close range, the 1.5-watt Boom Bit sounds pretty loud. I just wouldn't say it sounds good. It's smaller than an old transistor radio but the sound isn't much different. As you might expect, there's barely any bass and the speaker sounds strained and distorted when you push up the volume. But it does sound better -- or at least plays louder -- than your phone's speakers and people's voices sound clear during calls (little speakers like this are strongest in the midrange).