Fitting easily into a shirtpocket, this is the wireless speaker that provides superior quality sound, ideal for streaming music from audio devices such as iPhones or iPads. It connects to Bluetooth v2.0-enabled audio devices wirelessly up to 30' away and broadcasts sound from a patented twin-speaker assembly. Created by an ex-NASA engineer, it has been lauded by Sound & Vision as possessing the frequency response of expensive bookshelf speakers. The sophisticated 4-watt acoustic drivers produce both crisp highs and resounding low frequencies from a single 25mm dome, powered by field-focused, back-to-back neodymium magnets and a 1" dual voice coil. Low frequencies are augmented by an acoustic suspension bass driver, an innovative design that uses the speaker's rechargeable lithium battery as the mass for its "moving wall" passive bass radiator, a miniature version of the kind found in larger subwoofers. The speaker can also connect directly to an additional subwoofer in addition to any audio device using a standard audio cable (not included). A four-hour charge of the rechargeable battery using the included AC adapter (12 hours using the mini-USB adapter) provides up to five hours of cordless operation. 5 1/2" W x 2" H x 1 1/4" D. (8 1/2 oz.)