The foundation of the system, an attractive silver, card-sized 32mb digital audio player, holds about two look hours of music and is powered by a single AAA battery that pops into the back. Battery life is fairly limited; enclosed literature claims eight hours on a single cell, but mine was closer to five or six hours. The included CD made software installation a breeze, even for this low-tech Luddite, and downloading MP3 music files on to the player was simple once I got the hang of it. I chose to mount the unit on the back of my helmet, as pictured, and run the speakers inside, tucked behind the liner within an existing cavity. To my delight, ear chafing from speaker protrusion was minimal, and the sound came across clearly at low speeds. At highway speeds over 60 miles per hour, however, the liner, wind, and ambient noise entering between the speakers and my ear canal conspired to muffle the audio significantly--even at full volume--resulting in only faint echoes of trebly sound. But that's probably a good thing; you don't want piped-in sound to be so loud as to drown out traffic use around you. Another complaint: the volume/power controls positioned on the unit's face are too small to manipulate accurately with gloved fingers.