Very simple, crystal clear sound. Picks up everything in the room with the kindle and then broadcasts it to your amazon echo/google home/bluetooth speakers. The app requires your smartphone or tablet/kindle to have bluetooth along with being able to pair with bluetooth speakers. Works with the amazon dot and other amazon echo devices as well as google home speakers. No ads; the app picks up every sound you speak into the first device and broadcasts it crystal clear to wherever your bluetooth stereo or amazon echo device is at. To use, set volumes on both devices to low. Amazon and google devices respond to your voice commands with alexa, etc. Connect your phone or tablet/kindle to your bluetooth speaker. Open the app and it will automatically play everything heard in the other room on the speaker/amazon/google device. To avoid feedback, please have the echo and smartphone/tablet at some distance. Works great and you will hear everything you say in a crystal clear fashion. To use alexa, hold the home key until the tablet dims and say, "Alexa lower volume" or "Alexa raise volume," i.e. Use as a spy app. Noise suppressor function, echo cancellation function, and automatic gain control where applicable. To use the app as designed, drag your finger down from the top of your kindle and turn on bluetooth. Then say "Alexa, pair bluetooth" to the amazon echo. You'll get your intercom when you speak into the kindle, interrupting alexa's voice.