Mediabridge Concerto - Bluetooth Speaker w/ 60W Amp - Dual 3" Midrange/Tweeter Drivers - 5.25" Woofer (Part# BTS-A2B ) No batteries: plug-in design allows for more power behind the sound, no batteries or recharging necessary Loud & clear: at 60W, This is the most powerful Bluetooth speaker for the price. Powerful subwoofer: a 5.25" downward-firing subwoofer creates full-bodied Deep bass to complement the acoustic drivers. Powerful subwoofer: an enormous 5.25 inch downward-firing subwoofer creates full-bodied Deep bass to complement the crystal clear acoustic drivers. Bluetooth: stream music & Audio via Bluetooth V4.0 from your smartphone, tablet, MP3 player & more. Bluetooth speaker with subwoofer, wireless speakers Bluetooth, wireless speaker Bluetooth, Bluetooth wireless speaker, Bluetooth speaker with bass, Bluetooth speaker electronics