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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-28 · 7 min read · Independent comparison
• KOPIDOE's biggest strength: true bone conduction drivers in 0.8g earbuds with a memory titanium alloy hook — about as minimal as open-ear gets, and it keeps your ear canal completely free.
• KOPIDOE's biggest trade-off: IPX5 only, no charging case, no app, and no noise control of any kind. Sweat and light rain are fine; the shower and the pool are not.
• Cleer ARC 4's biggest strength: Dolby Atmos with head tracking, Snapdragon Sound with aptX Adaptive and Lossless, 34 hours of total playtime, and an IPX7 build that handles rain and hard training.
• Cleer ARC 4's biggest trade-off: it's a bulkier hook-style earbud in a plastic charging case, and all that processing means more to manage — firmware, app settings, multipoint pairing.
• Pick KOPIDOE if you want the lightest possible awareness-first earbud for sleep, yoga, cycling and commuting.
• Pick Cleer ARC 4 if you want movie-grade spatial audio, long battery and the freedom to get rained on.
The KOPIDOE B20 is a true bone conduction design. Instead of firing sound into your ear canal, it transmits through temporal bone vibration, which is why your ears stay completely open. In practice that means you hear traffic, a training partner, or a referee's whistle while your music keeps playing. The brand also builds a directional sound transmission structure into the driver to contain leakage, so what you're listening to stays mostly yours rather than broadcasting to the rowing machine next to you.
The headline number here is 0.8g per earbud. That is genuinely tiny, and it's paired with a memory titanium alloy ear hook and skin-friendly medical-grade silicone. For anyone who has given up on earbuds because they ache after an hour, this is the whole pitch: an ergonomic hook that stays put through running and lifting without pressing on the ear canal. The enclosure is silicone and titanium alloy, the driver is a bone conduction unit covering 20Hz–20,000Hz at 30 ohm impedance, and there's no headphone jack — it's wireless only, over Bluetooth 5.4 with a 10-meter range.
On controls, it's touch-based: tap to play or pause, skip tracks, answer calls. There's a built-in mic for calls and voice assistants, and the brand positions it as portable and easy to carry for sports and daily travel. The water story is honest but limited — IPX5 with a sealed construction handles heavy sweating and accidental rain, but the brand explicitly warns against rinsing, submerging, or showering with them. There's also no noise control and no companion app, so you get what the hardware does and nothing more.
Who should buy it: sleepers and side-sleepers who want something almost weightless, yoga and gym people, cyclists and commuters who prioritize hearing their surroundings, and anyone who wants bone conduction without a headband. Who should skip it: swimmers, people who want a charging case to top up on the go, listeners who want EQ tweaking or spatial audio, and anyone who needs more than light-rain protection.
The Cleer ARC 4 Plus is a different animal. It's still open-ear — hook-shaped earpieces that sit outside the canal so ambient sound comes through — but it leans hard into audio processing rather than pure minimalism. Dolby Atmos with precise head tracking recreates a 3D surround field for movies, games and music, and Snapdragon Sound with aptX Adaptive and Lossless support pushes high-resolution wireless audio. DBE 4.0 bass enhancement fills in the low end that open-ear designs often lose. The driver here is a dynamic driver, also rated 20Hz–20,000Hz.
Battery is the other big differentiator: 9 hours per charge plus 25 more from the charging case, for 34 hours total, with a 10-minute quick charge giving 3 hours of playtime. A full charge takes about 2 hours. The case itself is compact plastic — roughly 3.3 by 2.36 by 0.8 inches and 97g — so it slips into a pocket or bag without drama.
Durability is a step up too. IPX7 means sweatproof and rainproof, and the build uses metal, plastic and silicone with materials the brand says resist scratches. Connectivity is Bluetooth 5.4 with multipoint: pair two devices and switch between them without repairing, which matters if you're jumping between a laptop call and your phone. Dual noise-canceling microphones handle voice pickup, and the Cleer+ app lets you customize EQ, update firmware and program the touch controls. Voice control is supported alongside touch and app control, and there's volume control on the earpieces. Cleer includes a 1-year warranty.
Who should buy it: runners, cyclists and commuters who want awareness plus real audio quality, movie and game fans who want head-tracked spatial sound, people who hate charging daily, and anyone who works across two devices. Who should skip it: side-sleepers (a hook design with a case isn't a sleep bud), swimmers — IPX7 is water-resistant, not for swimming — and buyers who want the absolute lightest, simplest thing on their ears.
• Best for sleep and side-sleeping → KOPIDOE Bone Conduction Headphone. 0.8g per earbud with a titanium alloy hook is about as low-profile as open-ear gets.
• Best for battery life → Cleer ARC 4. 9 hours per charge plus 25 from the case, with a 10-minute quick charge adding 3 hours.
• Best for water and sweat resistance → Cleer ARC 4. IPX7 versus IPX5, and KOPIDOE explicitly warns against rinsing or submerging.
• Best for sound quality and immersion → Cleer ARC 4. Dolby Atmos with head tracking, Snapdragon Sound, aptX Adaptive and Lossless, plus DBE 4.0 bass enhancement.
• Best for pure bone conduction → KOPIDOE Bone Conduction Headphone. It uses an actual bone conduction driver; the ARC 4 uses a dynamic driver in an open-ear hook.
• Best for keeping it simple → KOPIDOE Bone Conduction Headphone. Touch controls, Bluetooth 5.4, no app, no case, nothing to configure.
• Best for multitasking across devices → Cleer ARC 4. Multipoint pairing lets you switch between two connected devices instantly.
• Best for tweaking your sound → Cleer ARC 4. The Cleer+ app gives you EQ customization, firmware updates and programmable touch controls.
If I had to pick one, I'd buy the Cleer ARC 4 Plus. In my opinion the combination of IPX7, 34 hours of total battery, multipoint and spatial audio simply covers more of real life — workouts, commutes, calls, and long trips where charging is a hassle. That said, the KOPIDOE is the smarter choice if weight is your whole reason for going open-ear. At 0.8g per bud it disappears on your head in a way a hook earbud with a case never will, and if you want to fall asleep listening to something, that matters more than any audio feature.
FAQ
how to bone conduction earphones work
how to wear bone conduction earphones
You hook them over the top of your ear so the transducer rests against the bone just in front of your ear, not inside the canal. The KOPIDOE uses a memory titanium alloy ear hook with medical-grade silicone to hold that position securely across different ear shapes, even during running and workouts.
how are bone conduction earphones different from regular earbuds
Regular earbuds seal or sit in the canal, which muffles the outside world and can cause discomfort over time. Open-ear bone conduction keeps the canal free — no pressure, no blocked feeling — and the trade-off is less isolation, which is exactly why KOPIDOE's design is aimed at awareness during commutes and sport.
do these open-ear earphones leak sound
KOPIDOE states its directional sound transmission structure is designed to contain leakage and keep listening private. The Cleer ARC 4 Plus doesn't publish a leakage spec, but its open-ear hook design also sits outside the canal rather than sealing it, so both are built around awareness rather than isolation. If leakage matters to you in quiet spaces, check the current price on Amazon and read the latest buyer feedback before deciding.
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