We once called this waterproof Bluetooth speaker 'the ultimate audio solution on the go' — and now it's just 100 bucks for Black Friday

Two people on yoga mats using the Ultimate Ears Boom 4 wireless speaker (Image credit: Ultimate Ears)

Forget Cyber Monday, there are still plenty of Black Friday speaker deals worth checking out if you're planning to upgrade your audio setup this holiday season. Head to Amazon right now, for instance, and you can save an epic 33% on the Ultimate Ears Boom 4, a leftover Black Friday discount that knocks the price of the speaker down to only $99.95.

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Sleek and portable, the Ultimate Ears Boom 4 topped our list of the best Bluetooth speakers for Android users, and it isn't hard to see why. This little cylindrical speaker is beloved for its versatility, with a design that's small enough to throw into a backpack and loud enough to entertain a whole party.

It's also more high-tech than it looks, with the ability to pair up to 150 Ultimate Ears speakers at once, customizable EQ settings, and up to 15 hours of battery life on a single charge. And of course, like any Bluetooth speaker we'd recommend, the Boom 4 is incredibly durable, with IP67 water and dust resistance. It even floats when you throw it in the pool!

As for negatives, there aren't many. As someone who still likes to use an aux cable from time to time, I do find it a little odd that the Ultimate Ears Boom 4 doesn't have an audio input jack. And of course, if money isn't an object, you can definitely find speakers that sound better (Bang & Olufsen, anyone?). But if you're looking to be the life of the party and you need a waterproof speaker for around 100 bucks, this is an awesome opportunity.