The Audio in connectivity allows direct playback of Audio in content from portable media players. Besides the benefit of enjoying your favorite music in the superior sound quality delivered by the audio system, the Audio in is also extremely convenient as all you have to do is to plug your portable MP3 player to the audio system. Bring massive sound wherever you need it, upstairs, downstairs, indoors or out. NITRO audio solutions slip smoothly into any home thanks to their optimized footprints and clutter free, convenient controls integration. Link them up with your TV or PC to supersize your experience and make music and movies sound bigger than ever. Or move them outside using built-in handles and wheels to turn them into the ultimate outdoor party sound system. Bluetooth is a short range wireless communication technology that is both robust and energy-efficient. The technology allows easy wireless connection to iPod/iPhone/iPad or other Bluetooth devices, such as smartphones, tablets or even loptops. So you can enjoy your favorite music, sound from video or game wireless on this speaker easily. Thanks to the complete file transferability, you can easily enjoy the convenience and fun of accessing more digital music via the built-in USB Direct and SD card slots. Get everyone up and dancing with party light effects. Colored lights on the speakers pulse in time to the music, flash in different orders, or stay on in a steady glow.