Vaux is $49 accessory for the second-generation Amazon Echo Dot from a new startup called Ninety7 that essentially turns Amazon’s miniature Alexa device into a portable, battery-powered Wi-Fi speaker.

To set it up, you simply slot your Echo Dot into the unit, and connect the built-in Micro USB and 3.5mm audio cables and you’re good to go. Vaux then recharges off the regular wall plug that you’d ordinarily use for your Echo Dot. Vaux also features a more powerful speaker than the Echo Dot’s own integrated one, which should help improve music playback on the device.

There are a few catches: Vaux isn’t waterproof or water-resistant. Charging it back up will take a while: between five and six hours if you’re not actively using it, and up to eight to 12 hours if you are. On top of that, once you’ve got it fully charged, Ninety7 estimates a battery life of around six hours — impressive for an untethered wall appliance, but not great for a portable speaker.

Vaux still requires Wi-Fi to function, so its portability is limited

It’s especially important to note that Vaux still requires Wi-Fi to function, so its portability is limited by the range of your home network. Coupled with the limited battery life and $49 price tag, it’s worth questioning whether it would simply be better to invest in a second Echo Dot to place in another room instead.

Also, if you’re looking for a portable Alexa device, it’s worth considering the fact that Amazon already sells one in the form of the portable Amazon Tap speaker, which as of last month supports the Echo’s always-listening hands-free mode. The Tap has Bluetooth in addition to Wi-Fi for playing music from local devices, and gets up to eight hours of battery life, although at $129.99, it is a bit pricer than the combined cost of the Vaux and an Echo Dot.

That said, if a portable Echo Dot is something you’ve wanted in your life, the Vaux certainly looks like it can make that happen. The Vaux is available to preorder today from the Ninety7 website for $49 in either Ash (white) or Carbon (black) colors. Ninety7 plans to ship the first units later this year in April.