Soundfreaq Sound Stack Speaker Dock for iPhone, iPod, iPad, and Other Bluetooth Devices, (Black) Stream audio wirelessly from any smart device with Bluetooth wireless A2DP compatible plus Bluetooth lossless streaming of AAC files with iOS devices. Custom engineered, Kevlar-reinforced drivers, 2 x 3 inch full range speakers, 2 x 3 inch dual Dub-Sub sub-woofer in push-pull configuration. UQ3 Spatial enhancement expand the sound stage, giving a more immersive audio experience that sounds natural and spatially engaging. Digital Optical audio line in accepts input from any device with Optical line out including Apple TV. USB charging port provides variable power up to 2.5V to charge mobile phones, smart phones, headsets and other portable devices with USB charging interface.