Matrix Audio MNRGBKM NRG Rechargeable 3W Pocket Speaker for iPhone/iPod/iPad - Retail Packaging - Black Patented Xcavated Bass Amplifier(XBA) Embedded universal 3.5mm auxiliary input compatible with iPod, iPad, iPhone and most other portable audio devices/cell phones. Powerful 40mm drivers and 3 watts oooomph. Patented buddy system enables users to attach multiple speakers for extra oooomph. Built in rechargeable battery delivers upto 14 hours playback. Rechargeable Fits in your pocket powerful