At just 7mm thick and 50 grams in weight, this is one of the most compact MP3 players on the market. It has a 1.8in OLED screen and offers up to 8GB of Flash storage, making it possible to store up to 4000 tracks. There's also an FM tuner and 3D sound. The battery offers up to 25 hours playback time. Available in blue, green and red.