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If you want a secure, anti-slip fit for your existing AirPods Pro 2 — including keeping them locked in during a swim — choose Proof Labs 4; if you need a standalone pair of open-ear earbuds with long battery life for swimming, running and workouts, choose Kncfoeb AI True Open.
• Proof Labs 4 — biggest strength: soft silicone over-ear hooks that stop AirPods Pro 2 from slipping out, sold in two sizes with a storage pouch and carabiner.
• Proof Labs 4 — biggest trade-off: these are covers, not earbuds. They only work with AirPods Pro 2nd Generation, and you must remove them before charging.
• Kncfoeb AI True Open — biggest strength: a genuine pair of open-ear clip-on earbuds with 45 hours of total playtime, ENC noise cancellation, four microphones and a water-resistant build.
• Kncfoeb AI True Open — biggest trade-off: open-back design means you hear your surroundings and lose some bass isolation — that's the point of the format, but it isn't for everyone.
• Buy Proof Labs 4 if you already own AirPods Pro 2 and just want them to stay put.
• Buy Kncfoeb AI True Open if you want one self-contained headset for sport, travel and all-day wear.
Proof Labs 4 is a fit accessory, not a listening device. It's a set of soft, flexible silicone hooks that wrap over the top of your ear to hold AirPods Pro 2nd Generation in place. The pitch is simple: AirPods Pro are great earbuds, but they can work their way loose during movement, and these hooks stop that. Because the enclosure is silicone, the material is grippy against skin and flexible enough to fold around the stem without adding much bulk.
What you get in the box is worth spelling out: two pairs in Small and two pairs in Large, plus a storage pouch, a carabiner and a quick start guide. That's four hooks total, which matters because small accessories like this get lost. The pouch and carabiner mean you can clip the spares to a bag or a keyring instead of hunting for them in a drawer. Proof Labs also backs the set with its Fit Guarantee and a one-year manufacturer warranty, which tells you the company expects sizing to be the main thing buyers worry about.
There is one quirk you need to accept before buying: the hooks must be removed before charging. That's because they cover the part of the AirPods Pro 2 that has to make contact with the case. It's a small routine — pop them off, charge, pop them back on — but if you want something you never think about, this isn't it. Also, these only fit AirPods Pro 2nd Generation. If you own any other earbuds, or you want earbuds at all, skip this entirely and look at the Kncfoeb instead.
So who is Proof Labs 4 actually for? Someone who already loves their AirPods Pro 2 and has one specific complaint: they don't stay in. If that's you, this is a cheap, low-risk fix. If you're shopping for your first pair of sport earbuds, this is the wrong product category.
Kncfoeb AI True Open is a complete open-ear headphone system built around a clip-on, over-ear hook design. Each earbud weighs just 8 g and the clamping arm is made from soft, ergonomic material that the brand says suits over 99% of ear shapes. The open-back design is the defining feature: the driver sits outside your ear canal, so music plays while you stay aware of traffic, teammates, or a coach shouting instructions. For outdoor running and cycling, that's a genuine safety argument, not a marketing one.
The spec sheet is unusually complete for this category. You get a 13 mm dynamic diaphragm driver, four high-precision microphones, and ENC (Environmental Noise Cancellation) to filter background noise on calls. Controls are touch-based, and the earbuds are explicitly designed to be worn with glasses — a detail most clip-on models ignore, and a real annoyance if you wear frames every day. Charging is USB-C, with 7–8 hours of playback per charge and up to 45 hours total from the charging case.
Water resistance is rated IPX5, which means sweat and rain are fine. I want to be precise about that, because "waterproof" gets thrown around loosely in this category: IPX5 handles spray and perspiration, but it is not a rating for submerging the earbuds in a pool. For swimming, treat these as a headset you wear to and from the water, on the pool deck, and through sweaty training blocks — and keep the charging case dry.
The Bluetooth side uses a Bluetooth 6.0 chip with AI-assisted pairing, low latency and a stated range up to about 33 feet (10 meters). The housing is lightweight PC alloy, black, and small enough to slip into a pocket. The open-ear format does mean you sacrifice some bass depth and passive isolation — that's the honest trade-off, and it's the same trade-off every open-ear design makes.
Side-by-Side: Which Should You Choose?
• Already own AirPods Pro 2 and they fall out → Proof Labs 4. That's the entire job it does.
• Long battery life bluetooth headset for swimming → Kncfoeb AI True Open, with 7–8 hours per charge and up to 45 hours with the case. Proof Labs 4 has no battery at all.
• Sweat-resistant training and gaming → Kncfoeb AI True Open. IPX5 plus an 8 g per-bud weight makes it the far better fit for long sessions.
• Wear glasses daily → Kncfoeb AI True Open. The clip-on arm is specifically shaped for frames.
• Need to hear traffic or a coach → Kncfoeb AI True Open. The open-back design keeps you aware; Proof Labs 4 keeps AirPods sealed in your ears.
• Want the smallest possible spend to fix a fit problem → Proof Labs 4, since it upgrades gear you already own.
• Need a case, cable and spares in the box → Kncfoeb AI True Open ships with a charging case and USB-C cable; Proof Labs 4 ships with four hooks, a pouch, a carabiner and a guide.
If I were spending my own money for swimming, running and everyday training, I'd buy the Kncfoeb AI True Open. It's the only one of the two that is actually a headset — with a 13 mm driver, ENC call clarity, IPX5 water resistance, 45 hours of case-backed playtime and a glasses-friendly clip. The Proof Labs 4 is a well-thought-out fix for a specific problem, and if your AirPods Pro 2 keep slipping, it solves that problem cleanly. But it can't do anything on its own, and it has to come off before every charge. Two different jobs. For sport, I pick the earbuds.
FAQ
How to put on ear clip earbuds
How to wear ear hook earbuds
Slide the hook over the top of your ear first, then settle the speaker into position. Proof Labs 4 works the same way but wraps around AirPods Pro 2 rather than a built-in driver — and remember those hooks must be removed before charging. Take a minute to test the fit with a head shake before you head out.
How to wear earbuds with ear hooks
If you wear glasses, put your frames on first, then position the hook so it sits between your temple and your ear rather than on top of the arm. Kncfoeb states the W2 is designed for glasses wearers and uses soft material specifically so the two can coexist. If it feels tight, try reseating the arm slightly higher or lower.
Are ear hook earbuds good
For sport, yes — in my opinion they're one of the better formats. The over-ear hook stops the bud from dropping out during running or lifting, and open-back models like the Kncfoeb AI True Open let you hear your surroundings. The trade-off is less bass and less isolation, so they're a poor choice if you want to block out a noisy commute. Check the current price on Amazon before deciding.
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