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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-25 · 6 min read · Independent comparison
• RELAXYO's biggest strength: IP68 waterproofing plus 32GB of built-in storage and an MP3 mode, so you can swim without carrying a phone.
• RELAXYO's biggest trade-off: Bone conduction means no in-ear seal, so no noise isolation and no deep bass — and it has no microphone array for calls.
• Acjohtin's biggest strength: Up to 90 hours of total playback with the charging case, Bluetooth 6.1, four ENC microphones, and 16.2mm drivers for real bass.
• Acjohtin's biggest trade-off: IPX7 handles sweat, splashes and rain, but it is not built for swimming, and in-ear tips mean you have to hear yourself breathe.
• Pick RELAXYO if swimming is on your list or you want your ears open to traffic on the bike.
• Pick Acjohtin if cycling, running and the gym are your main sports and you want long battery life and calls.
The RELAXYO X7 is built around one idea: keep your ears open and keep the water out. It uses a bone conduction driver rather than speakers that sit in your ear canal, so sound travels through your cheekbone and you stay aware of what's around you. For cycling that matters more than most people expect — you hear cars, bells and other riders without pulling an earbud out. The IP68 rating is the headline here, and it's paired with an open-ear hook design that RELAXYO says can be worn under a swim cap or with goggles.
The second half of the story is the 32GB of built-in media storage. That's the feature that makes this genuinely different from a normal pair of earbuds: you load songs onto the headphones themselves, switch from Bluetooth mode to MP3 mode, and swim without a phone anywhere near the pool. Bluetooth 5.4 handles the wireless side for running, cycling and everyday use, and the battery is rated at 7 hours per charge.
Who should buy it? Swimmers first, obviously. Then open-ear runners and cyclists who want situational awareness, and anyone who hates the plugged-up feeling of in-ear tips. Who should skip it? If your main goal is immersive sound — thumping bass, podcasts in a noisy gym, taking calls on the bike — this is the wrong tool. There's no noise control listed and no microphone array, so it's a listening device, not a headset. In my opinion it's a specialist, and it's very good at its speciality.
The Acjohtin YYK-Q15 is the opposite approach: a conventional true-wireless in-ear bud with over-ear hooks, loaded with the features people expect from a modern sports earbud. The numbers are the pitch — up to 90 hours of total playback with the case, 8 hours from a single charge, and an LED display that shows the battery level of both the buds and the case so you're not guessing before a ride.
The audio side is where it separates itself from generic earbuds. Acjohtin uses 16.2mm dynamic drivers, which is a large driver for this category, and claims punchy bass with balanced mids and treble. For cycling playlists, gym sets and podcasts, that's the experience most people actually want. The Bluetooth 6.1 chip is listed as faster and more stable than 5.4, with a 33ft range and low latency — useful if you're watching video on a trainer or gaming between rides.
Calls are a genuine feature here, not an afterthought: four HD microphones with ENC noise reduction that Acjohtin says blocks up to 45dB of background noise. If you take work calls or want to answer the phone mid-commute, that's a real advantage over the RELAXYO. The fit is handled by flexible silicone over-ear hooks plus S/M/L interchangeable tips, which is the right design for cycling — hooks keep buds locked in when you're bouncing over rough tarmac. IPX7 covers sweat, splashes and light rain. It also carries a 2-year warranty versus RELAXYO's 1 year.
Who should buy it? Cyclists, runners, gym-goers, commuters — anyone who wants one pair of earbuds for sport and daily life. Who should skip it? Swimmers. IPX7 is not an IP68 swimming rating, and in-ear tips plus water don't mix the way bone conduction does. If you want to hear traffic while riding, the sealed fit works against you.
• Best for swimming → RELAXYO Swimming Bone Conduction. IP68 plus MP3 mode with 32GB of storage means no phone required in the water.
• Best for cycling → Acjohtin Earbuds. Over-ear hooks and interchangeable tips stay locked in, and the 16.2mm drivers give you music you can actually feel over wind noise.
• Best for calls → Acjohtin Earbuds. Four HD mics with ENC noise reduction; RELAXYO lists no microphone or noise control at all.
• Best for battery life → Acjohtin Earbuds. Up to 90 hours with the case and 8 hours per charge, versus RELAXYO's 7 hours.
• Best for open-ear awareness → RELAXYO Swimming Bone Conduction. Bone conduction leaves your ear canal open, so you hear traffic on the bike.
• Best for bass and immersion → Acjohtin Earbuds. 16.2mm dynamic drivers versus a bone conduction driver with no in-ear seal.
• Best for a phone-free workout → RELAXYO Swimming Bone Conduction. The 32GB of built-in storage is the deciding feature if you don't want to carry a device.
• Best for warranty coverage → Acjohtin Earbuds. Two years against RELAXYO's one.
If I had to pick one, I'd buy the Acjohtin Earbuds. For cycling, running, the gym and commuting, they cover far more ground: long battery life, real bass, working microphones, a secure hook fit and a longer warranty. The RELAXYO is the better product for exactly one job — swimming and open-ear awareness — and it does that job in a way the Acjohtin simply can't. So my call is Acjohtin for most people, RELAXYO if the pool is where you train. Check the current price on Amazon before you commit, since that's the one variable that could flip the decision.
FAQ
No. Acjohtin is rated IPX7, which covers sweat, splashes and light rain — not swimming. The RELAXYO is rated IP68 and has a dedicated MP3 mode specifically so you can leave your phone behind in the water. If swimming is your sport, that's the one to take.
Yes, but only for calls. The four microphones use ENC noise reduction to block up to 45dB of background noise on your voice, so callers hear you clearly. There's no active noise cancellation for your music, so external sound still comes through.
Acjohtin, in my opinion. The over-ear hooks and S/M/L tips keep the buds in place during high-intensity training, IPX7 handles the sweat, and 90 hours of case battery means you rarely think about charging. RELAXYO's 7 hours is fine for a session, but you'll charge it more often.
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See also: RELAXYO Bone Conduction Swimming vs OceanSounds Open Ear Headphones, Matast Earbuds vs Sanag Swimming Bone Conduction, HIFI WALKER Bone Conduction Swimming vs DUSONLAP Open Ear Earbuds