Includes two Echo (2nd Gen) devices and one Echo Sub for a room-filling, wireless 2.1 stereo system. Echo Sub delivers down-firing, 100W deep bass sound through a 6" woofer. Pair with one Echo or Echo Plus (sold separately) to enjoy dynamic music that fills the room. Pair with two of the same Echo devices for rich left/right stereo sound. Simple to set up and use—just plug in, open the Alexa app, and wirelessly connect to your Echo device(s) to control music with your voice.