These sit in different size classes, so this is not a straight ranking comparison. The Ultimate Ears Boom 4 ranks #113 of 179 medium speakers by sound quality at $114.99; the Zealot S67 ranks #118 of 120 large speakers by sound quality at $70.94. Both are rated below 3.0/5 for their class (179 medium speakers and 120 large speakers), so if sound quality matters, look higher up the rankings.
The Ultimate Ears Boom 4 is the lighter choice. A tough waterproof speaker that floats, with USB-C charging, app EQ and pairing with other UE speakers. At 1.4 lbs (620 g) it weighs much less than the Zealot S67 at 5.3 lbs (2.4 kg). It has an adjustable EQ, which the Zealot S67 lacks. The tradeoff: Not much improvement over the old ones.
The Zealot S67 is the longer-running choice. A budget waterproof speaker with a long rated battery, USB-C charging, microSD playback, and stereo pairing. It is rated for 20 hours of battery against 15 for the Ultimate Ears Boom 4. It keeps a wired aux input, which the Ultimate Ears Boom 4 lacks. The catch: Sound quality is the catch.
Buy the Ultimate Ears Boom 4 at $114.99 if you want a medium speaker. Buy the Zealot S67 at $70.94 if you want a large speaker instead.
Looking for alternatives? See the complete Portable Bluetooth rankings.
Prices on this page were last checked November 7, 2026 at 7:34 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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Specifications Side By Side
| Ultimate Ears Boom 4 | Zealot S67 | |
|---|---|---|
| Price | $114.99 | $70.94 |
| Ranked | #113 of 179 in Medium Size Portable Bluetooth Speakers | #118 of 120 in Large Size Portable Bluetooth Speakers |
| App | Yes | No |
| Battery Life | 15 hours (Manufacturer specified) | 20 hours (Manufacturer specified) |
| IP Rating | IP67 | IPX6 |
| Power Input | USB-C | USB-C |
| Stereo | Yes | Yes |
| Omnidirectional | No | No |
| Weight | 1.4 lbs (620 g) | 5.3 lbs (2.4 kg) |
| Bluetooth | Yes | Yes |
| Bluetooth Version | 5.1 | 5.2 |
| Dimensions | 7.2” x 2.9” x 2.9” (184 x 73 x 73 mm) | 11.6” x 4.8” x 5.2” (294 x 122 x 132 mm) |
| Drivers | 2x 1.57” (40mm) active drivers + 2x 1.81” x 2.57” (46.1 x 65.2mm) passive radiators | 60W: Dual drivers + passive radiator |
| TWS | Yes | Yes |
| EQ | Yes (via app) | No |
| Built-in Microphone | No | Yes |
| Power Bank | No | No |
| Aux Input | No | Yes |
| Maximum SPL | 85dBC (Manufacturer specified) | - |
| Digital Aux Input | No | No |
| Bluetooth Codecs | SBC | SBC |
| Strap | Yes (built-in loop) | - |
| MicroSD Playback | - | Yes |
| Party Mode | - | No |
| Amplifier Power | - | 60W |
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