Bluedio US Wireless Bluetooth Satellite Speaker System with Mic(Black) 1. With it distinctive design, the Bluedio US builds its high-strength from an aluminum alloy for its main frame, which makes it lightweight and durable. The unique appearance reminds you of an UFO and will create interest at first sight. 2. The 2.1 sound track employs a 59mm bass driver and is designed to improve and strengthen low frequencies. The other two speakers can now concentrate on reproducing the mid and high tones. Music will be brilliantly rendered. 3. 3D sound: When you are watching movies or enjoying music, simply turn on the 3D sound and it will amplify the sound field and optimize the bass to bring you the experience of a home theater system. 4. Passive radiator: The specially designed passive radiator will assist the 59mm bass driver to effectively enhance bass performance. It sounds strong and powerful. 5. Control buttons: All 4 buttons are located on the top of the Bluedio US. Each key cap are separated by appropriate space to ensure you can accurately control your music .