AMAZON B07F3JK91W - The Echo Sub is a powerful subwoofer for your Echo devices that adds deep bass to your music playback. Pair the Sub with one Echo device for enhanced sound and music playback, or pair with two Echo devices for left/right stereo sound.6" 100W Down-firing woofer with Class D amplifierEasy setup, just connect to your existing Echo devices with the Alexa app 30Hz (-6dB) Low frequency response50-200Hz Crossover frequency Dual band 2.4/5GHz WiFi connectivityAuto switching 100-240V power supply (50/60Hz)ContentsEcho Sub, AC adaptor and user guideFootnotesNote: The Echo Sub is not a standalone product, requires at least one Echo device to function.