Connects VAIL Cast, a Works with Alexa universal streaming audio amplifier, to your Amazon account and stream music from Amazon’s music apps from any smart phone, Echo products and generations. and voice control with Alexa. Power any pair of indoor or outdoor speakers for a single room or whole house audio. Visit www.vanguarddynamics.com for info on other features like Chromecast built-in, Airplay2, Spotify Connect, Bluetooth, and DLNA.