JBL Charge Portable Wireless Bluetooth Speaker (Stealth Black) High Capacity, 6000mAh Li-ion Rechargeable Battery, A clearly visible LED lets you know when its built-in battery needs to be recharged as well as when the speaker is in the Bluetooth listening or pairing mode. The JBL Charge speakers high-capacity battery has so much juice that you can even use it to recharge your other portable devices from the speakers built-in USB port portable speaker streams audio wirelessly from any Bluetooth-equipped device, making JBL sound available for a wide range of portable devices, including tablets It has a built-in bass port and generates bass that similar portable speakers simply cant equal. With two 1-5/8-inch (41-mm) JBL drivers and a 2 x 5-watt amplifier, the JBL Charge generates room-filling audio  impressive performance for a compact speaker that goes anywhere with you.