KEF Gravity One is a wireless speaker with Bluetooth 4.0 featuring Qualcomm® aptX™ audio technology and 3.5mm AUX input. It features a 50mm Miniature Uni-Q driver, a 50mm full-range driver, and 2 Force-Cancelling Auxiliary Bass Radiators (ABRs) for a powerful and immersive listening experience. With up to 10 hours of battery life, you can enjoy your music all day long. The USB charging port allows you to charge your other devices while you listen to your music. The Gravity One also has a built-in microphone for hands-free calling, so you can take calls without having to disconnect your music.