The Perfect Sound 2 is an exemplary source for streaming audio to the listener's ear without the disruption of outer sources. Its closed leatherette ear cushions serve as maximum isolation to cancel out noisy environments for undisturbed listening. The domed enclosure helps to amplify and enrich sound from the 40mm cobalt magnet speakers. Located on the shell of the right headphone is the power switch and on the left is the battery insert that houses one AAA battery (not included). Also included is an airplane adaptor and carrying case for the mobile listener. Its battery life lasts up to 60 hours, assuring continuous life so that replacements don't become an annoyance. This comfortable and lightweight (180g) headphones is adjustable and collapsible, making it perfect for storage. Compatible with any audio system that has a headphone jack (iPod, MP3, computer and stereo systems), the Perfect Sound 1 is an optimum choice for listeners that enjoy the intimacy of music in their own privacy.