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If you want all-day everyday wireless earbuds with active noise cancelling for commuting, calls and gym sessions, choose CMF BY NOTHING Buds 2a; if you need headphones that keep playing music actually underwater while you swim, choose Opinta Swimming Headphones.
• CMF BY NOTHING Buds 2a – biggest strength: 42dB hybrid active noise cancelling with a 12.4mm dynamic driver, 8 hours per charge (35.5 hours with the case), four mics for calls, and app-based EQ — a full everyday earbud package.
• CMF BY NOTHING Buds 2a – biggest trade-off: IP54 only, so sweat and splashes are fine but swimming is not; and it relies on Bluetooth, which does not travel through water.
• Opinta Swimming Headphones – biggest strength: IPX8 waterproofing rated for use down to 3m, plus a built-in 32GB memory card so it plays MP3s with no Bluetooth signal at all.
• Opinta Swimming Headphones – biggest trade-off: No noise cancelling, open-ear bone conduction design (so less isolation and less bass punch than in-ear buds), and Bluetooth simply doesn't work underwater — you must switch to MP3 mode.
• Who each pick is for: CMF Buds 2a for commuters, call-heavy users and gym-goers who want ANC and app control; Opinta for swimmers and open-water athletes who need music in the pool.
The CMF Buds 2a is built around one idea: cover as many everyday listening situations as possible in a single pair of in-ear buds. The headline feature is 42dB hybrid active noise cancelling, which is the kind of figure that meaningfully dulls engine drone on a bus or train, air-conditioning hum in an office, and the general wash of noise in a busy gym. Around that sits a 12.4mm bio-fiber dynamic driver co-tuned with DIRAC, which CMF describes as delivering a warm soundstage with rich mids and punchy bass you can adjust or switch off entirely.
The practical stuff is well covered too. Bluetooth 5.4 handles the connection, with Google Fast Pair and Microsoft Quick Switch making pairing to a phone or laptop painless, while four ENC mics with wind noise reduction handle voice pickup on calls. Battery life is 8 hours in the buds and 35.5 hours with the case, and a 5-minute quick charge buys roughly 2 hours of playback — genuinely useful when you're walking out the door and realise you forgot to charge. The IP54 rating covers sweat, dust and light rain, and the whole thing weighs 42.75g with the case.
Who should skip it: swimmers. IP54 is a splash-and-sweat rating, not a submersion rating, and Bluetooth audio doesn't propagate through water anyway. If your main workout is laps in a pool, this isn't the tool.
Opinta Swimming Headphones: Who It's For
The Opinta Swimming Headphones (model X7 Pro) solves a problem most earbuds can't: music while you're actually submerged. It does that with two things working together. First, IPX8 waterproofing — the highest common water-resistance tier — rated for use to 3m depth and able to shrug off being submerged or hit with water pressure. Second, a built-in 32GB memory card that turns the headset into a standalone MP3 player. That second part matters more than it sounds, because Bluetooth signals don't transmit underwater. Opinta is upfront about this: you switch to MP3 mode before you get in the water, and you can't take calls or stream from your phone while you're under.
The design is open-ear bone conduction. Sound is delivered through the cheekbone rather than into the ear canal, which means nothing is jammed in your ears and your ears stay open to what's around you — a real safety plus when you're running or cycling near traffic. It's made from soft silicone, weighs only 30g, and Opinta says it won't fight with hats or glasses. There's also an adjustment strap in the box if the fit feels loose. Battery is a 200mAh cell giving up to 8 hours of playback or talk time, recharging in 2 hours via a magnetic port — which you must dry before charging to avoid damage.
Who should buy it: swimmers first and foremost, from pool lap swimmers to open-water and triathlon types. Also anyone who wants one headset that handles swimming, cycling, marathon training and hiking without worrying about water. The open-ear design suits people who dislike the plugged-up feeling of in-ear buds or who need to hear traffic.
Who should skip it: anyone who wants noise cancelling — there is none here. The open-ear bone conduction approach also trades isolation and deep bass for awareness, so if you want to shut out a noisy commute, this isn't it. And if your priority is Bluetooth calling and streaming throughout the day, the underwater-first design is simply the wrong shape of product.
Side-by-Side: Which Should You Choose?
• Best for noise cancelling → CMF BY NOTHING Buds 2a. 42dB hybrid ANC with adjustable levels and a transparent mode; Opinta has no noise control at all.
• Best for calls and meetings → CMF BY NOTHING Buds 2a. Four ENC mics, wind noise reduction and dual-device connectivity versus an open-ear bone conduction headset with no ANC.
• Best for battery flexibility → CMF BY NOTHING Buds 2a. 8 hours in the buds plus a 35.5-hour case, with a 5-minute quick charge for about 2 hours of playback.
• Best for staying aware of traffic → Opinta Swimming Headphones. The open-ear design leaves your ears unobstructed, which matters on roads and trails.
• Best for app control and customisation → CMF BY NOTHING Buds 2a. EQ profiles, ANC levels, find-my-buds, low-latency gaming mode and dual-device pairing via the Nothing X app.
• Best all-rounder for land-based life → CMF BY NOTHING Buds 2a. IP54, Bluetooth 5.4 and in-ear fit cover commuting, work and the gym.
• Best for a single headset across swim, bike and run → Opinta Swimming Headphones. One device, two modes, no need to swap gear between disciplines.
In my opinion, most people should buy the CMF BY NOTHING Buds 2a. It covers the situations you'll actually encounter most days — noisy commutes, calls, workouts, late-night listening — with ANC, a proper in-ear fit, a long-lasting case and deep app control. The Opinta is the better product only if swimming is genuinely central to your routine, because that's the one thing the CMF Buds 2a cannot do at all. If you swim laps weekly and want music in the water, buy the Opinta without hesitation. If you don't, the CMF Buds 2a is the smarter all-round pick.
No. It carries an IP54 rating, which covers sweat, dust and light splashes — not submersion. Bluetooth audio also doesn't transmit through water, so swimming isn't a use case for it.
No. Bluetooth doesn't work underwater, so you switch to MP3 mode for swimming. Take calls when you're out of the water and back in Bluetooth mode.
No. The data sheet lists noise control as none, and the open-ear bone conduction design intentionally leaves your ears open to your surroundings.
It depends on what you need. The CMF Buds 2a gives you ANC, four mics, app customisation and a charging case; the Opinta gives you IPX8 waterproofing, 32GB of built-in storage and an open-ear fit. Check the current price on Amazon for each and match it to your main activity.
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