Bose SoundLink Flex (2nd Gen) vs Ultimate Ears Boom 4

Bose SoundLink Flex (2nd Gen) vs Ultimate Ears Boom 4: which one should you buy?

Quick answer

Buy the Bose SoundLink Flex (2nd Gen) if you want a rugged speaker with natural sound. Buy the Ultimate Ears Boom 4 instead if you want sound that fills the space all around you.

By Buyrskip Editorial Team Updated November 2, 2026 1 min read

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Buy

Bose SoundLink Flex (2nd Gen)

Best for Clear, portable sound

Typically $129–$149

Check Price on Amazon Paid link

Buy

Ultimate Ears Boom 4

Best for 360-degree sound

Typically $129–$149

Check Price on Amazon Paid link

Quick comparison

Feature	Bose SoundLink Flex (2nd Gen)	Ultimate Ears Boom 4
Verdict	Buy	Buy
Typical price	$129–$149	$129–$149
Best for	Clear, portable sound	360-degree sound
Key feature	Clear, balanced sound in a tough, floating speaker	Loud 360-degree sound in a drop-proof, floating speaker
Water resistance	IP67	IP67
Battery	Up to 12 hours	Up to 15 hours
Weight	0.6 kg	0.7 kg
Stereo pairing	Yes	Yes (PartyUp)
Where to buy	Check Price Paid link	Check Price Paid link

Main differences

Water resistance

Bose SoundLink Flex (2nd Gen): IP67; Ultimate Ears Boom 4: IP67.

Battery

Bose SoundLink Flex (2nd Gen): Up to 12 hours; Ultimate Ears Boom 4: Up to 15 hours.

Weight

Bose SoundLink Flex (2nd Gen): 0.6 kg; Ultimate Ears Boom 4: 0.7 kg.

Stereo pairing

Bose SoundLink Flex (2nd Gen): Yes; Ultimate Ears Boom 4: Yes (PartyUp).

Why buy it

Bose SoundLink Flex (2nd Gen): clear, balanced sound in a tough, floating speaker; Ultimate Ears Boom 4: loud 360-degree sound in a drop-proof, floating speaker.

Made for

Bose SoundLink Flex (2nd Gen): clear, portable sound; Ultimate Ears Boom 4: 360-degree sound.

Usual price

Bose SoundLink Flex (2nd Gen): $129–$149; Ultimate Ears Boom 4: $129–$149.

Which should you choose?

Choose the Bose SoundLink Flex (2nd Gen) if you

you want a rugged speaker with natural sound
value clear sound

Check Price Paid link

Choose the Ultimate Ears Boom 4 if you

you want sound that fills the space all around you
value 360° sound

Check Price Paid link

If neither feels right

Neither is the only answer. See every model we would buy (and the ones we would skip) in our list of the best bluetooth speakers.

Not sure about either? Consider these

JBL · Speakers

JBL Flip 7

Buy it if you want one tough speaker for the backyard, pool and trips.

Verdict: Buy
Best for: Most people
Typical price: $129–$149

Pros

IP68 waterproof and drop-proof
Auracast multi-speaker

Cons

Mono sound

Check Price on Amazon Paid linkRead our review

Bose · Speakers

Bose SoundLink Max

Buy it if you want a speaker that fills a backyard and still has a handle.

Verdict: Buy
Best for: Big sound
Typical price: $299–$399

Pros

Big, balanced sound
IP67

Cons

Expensive

Check Price on Amazon Paid linkRead our review

Frequently asked questions

Bose SoundLink Flex (2nd Gen) or Ultimate Ears Boom 4: which should I buy?

Buy the Bose SoundLink Flex (2nd Gen) if you want a rugged speaker with natural sound. Buy the Ultimate Ears Boom 4 instead if you want sound that fills the space all around you.

Is the price difference worth it?

The Bose SoundLink Flex (2nd Gen) usually costs $129–$149 and the Ultimate Ears Boom 4 $129–$149. Pay more only if the differences above matter to you.

Buyrskip Editorial Team

Part of the Buyrskip research team. We compare specifications, documentation and real-world trade-offs so you can decide faster.

How we research products Editorial policy

Bose SoundLink Flex (2nd Gen) or Ultimate Ears Boom 4: the full reasoning

Bose SoundLink Flex (2nd Gen) or Ultimate Ears Boom 4? Both are strong bluetooth speakers, which is exactly why the choice is hard. Here is the short version first: buy the Bose SoundLink Flex (2nd Gen) if you want a rugged speaker with natural sound, and buy the Ultimate Ears Boom 4 if you want sound that fills the space all around you. The rest of this page explains why, with usual US prices.

Where they differ

The Bose SoundLink Flex (2nd Gen) wins on clear, balanced sound in a tough, floating speaker. The Ultimate Ears Boom 4 answers with loud 360-degree sound in a drop-proof, floating speaker. Water resistance: IP67 on the Bose SoundLink Flex (2nd Gen), IP67 on the Ultimate Ears Boom 4. Battery: Up to 12 hours on the Bose SoundLink Flex (2nd Gen), Up to 15 hours on the Ultimate Ears Boom 4. Weight: 0.6 kg on the Bose SoundLink Flex (2nd Gen), 0.7 kg on the Ultimate Ears Boom 4. Stereo pairing: Yes on the Bose SoundLink Flex (2nd Gen), Yes (PartyUp) on the Ultimate Ears Boom 4.

Reasons to buy the Bose SoundLink Flex (2nd Gen)

Clear sound, Floats, Rugged. What to accept: 12-hour battery, mono. Usual price: $129–$149. Our verdict: buy. Read the full Bose SoundLink Flex (2nd Gen) review.

Reasons to buy the Ultimate Ears Boom 4

360° sound, Floats, Very rugged. What to accept: no app EQ depth, bass is moderate. Usual price: $129–$149. Our verdict: buy. Read the full Ultimate Ears Boom 4 review.

Neither one?

Our list of the best bluetooth speakers has every other model with its own call. Waterproofing: IP67 survives the pool, the beach and rain.

Also consider the JBL Flip 7 ($129–$149): punchy sound, IP68 toughness and Auracast in a bottle-size speaker. Buy it if you want one tough speaker for the backyard, pool and trips.

Also consider the Bose SoundLink Max ($299–$399): rich stereo sound and deep bass from a carryable speaker. Buy it if you want a speaker that fills a backyard and still has a handle.

US buyer tip

For backyard and pool use, a rugged IP67 speaker is the safest buy; check whether the brand sells replacement batteries or offers a long warranty.

Prices on Amazon.com move in a pattern. The deepest cuts land on Prime Day in July, Prime Big Deal Days in October and the Black Friday to Cyber Monday week, with smaller drops around Presidents Day, Memorial Day, the Fourth of July and back-to-school. Judge a deal against the usual price we show, never against the crossed-out list price.