Truth be told, when I took Monster Superstar S100 ($60) out its box, I didn't have high hopes for it. That's because when it comes to tiny Bluetooth speakers, my expectations -- particularly when it comes to sound quality -- are usually pretty low. (It costs £100 in the UK, and doesn't appear to be available in Australia, where the US price converts to about AU$80.)
But it turns out this is a decent mini Bluetooth speaker. While it's small enough to fit within the palm of your hand, it feels substantial enough, weighing in at 0.45 pound or 204 grams. It's fully waterproof (it has anrating which means it can be fully submerged) and has a set of rubber feet on the bottom so it doesn't move around when you crank the volume.
The features list is pretty basic. There's an integrated microphone for speakerphone calls (callers said they could hear me fine) and underneath a gasket on the side of the speaker you'll find the Micro-USB charging port and an audio input. A lanyard is included so you can attach the speaker to your backpack or hang it from a tree branch -- or anything you can hook the lanyard on to.
The multifunction button on the speaker allows you to turn the speaker on, pause and play tracks and answer and end calls, but there are no volume controls or track skip buttons -- you have to control playback remotely through your Bluetooth-enabled device.