Fiio E5 Headphone Amplifier, 10 to 100KHz Frequency, 3.5mm Input/Output

The Fiio E5 Ultra-Portable Headphone Amplifier (Black) provides audio enhancement to your portable music player in an incredibly compact design. The amplifier has a similar design to the iPod shuffle and even has a metal clip for convenient attachment to your clothes. It offers power and volume controls, as well as an EQ switch that lets you switch between flat and bass boost modes.

The amplifier has standard 3.5mm input and output connectors for compatibility with a variety of music players and headphones. The amplifier has a built-in Li-ion rechargeable battery that is charged via a mini USB connection. A blue/red bi-color LED shows operation and charging status.