The Ultimate Ears WONDERBOOM 4 is the rare speaker that actually gets *louder* in the places you want to use it most. Its 360-degree sound bounces off pool decks, shower tiles, and rocky trails with surprising clarity. The bass stays punchy even when you crank the volume, and the design is pure function: a dense plastic orb that weighs under a pound and fits in a water bottle holder. It floats. That is not a marketing gimmick—drop it in a lake and it bobs right back to the surface.

The IP67 rating means dust and submersion up to a meter for 30 minutes are non-issues. The 14-hour battery covers a full day at the beach or a week of shower playlists. Pairing is standard Bluetooth, but the real trick is that you can wirelessly link two WONDERBOOM 4 speakers together for true stereo separation. The range holds steady at about 40 meters outdoors, which is enough to keep the music going while you swim laps or wander the campsite.

One honest note: the charging still uses micro-USB, not USB-C. That feels dated in 2024 and means one more cable to carry. The sound is clear and loud for its size, but it won’t fill a large backyard party with deep bass—it’s built for close-range, rugged, outdoor fun. For the person who wants music at the pool without worrying about their speaker, this is the one.