The Fireye Mini will allow you to enjoy your favorite songs with higher-quality sound through your portable music player (MP3 player, iPod, smartphone, etc) anywhere, anytime. This mini amplifier will boost up volume and dynamics, increase sound quality, and improve bass response and authority of virtually any portable music player with a 3.5mm headphone output. With a built-in lithium battery, you can feel free to listen to music with up to a 24 hours of playback time and simply recharge it afterwards via a USB port. The Fireye mini easily fits in a pocket or purse making it easy to bring with you where ever you go, allowing you to enjoy imporved music quality on the go. Use the Fireye mini to amplify the signal of your headphone, and change the way you listen to music today. Please note: This unit is not suitable for amplifying signal that is going to another amplifier, like car radio, etc. You connect the output of Fireye Mini direct to any normal speaker; instead use a headphone with impedance 32 to 600 Ohm.