Amazon has announced the Echo Sub, a new subwoofer accessory that can be wirelessly paired with either a 2nd-gen Amazon Echo or the new 2nd-gen Echo Plus to add more bass to your music. It features a 6-inch downward-facing subwoofer with 100 watts of power. It can also be used with a pair of Echos to create a stereo 2.1 sound system, where each Echo acts as either the left or right channel. The Echo Sub is available to pre-order now for $129.99 and will arrive on October 11th. You can also order a bundle that includes the Echo Sub and two Amazon Echos for $249.97, which saves you $80 versus buying each item individually.

The Echo Sub has a low-frequency response of 30Hz (-6dB) and a maximum acoustic output of 103dB. It has a 120 Hz – 150 Hz adaptive low-pass crossover frequency. It connects via dual-band 802.11 a/b/g/n Wi-Fi on either 2.4GHz or 5GHz bands.

Amazon currently says that the Echo Sub is “only optimized for Echo (2nd Gen) and Echo Plus (2nd Gen).” While that leaves them open to add support for the 1st-gen Echo, 1st-gen Echo Plus, and possibly even Fire TV devices in the future, the Echo Sub is not currently compatible with those other Alexa devices. It only connects via WiFi, so there is no audio-in port on the Echo Sub to connect it to anything other than supported Echos.

The Echo Sub is wrapped in a fabric mesh that is only available in a “Charcoal” color that is a dark grey, but not quite black. It does not appear to have any kind of controls. The Echo Sub is set up through the Alexa app to be paired with an Echo device and then simply left alone to add much-needed bass to Alexa’s music playback.