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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-22 · 7 min read · Independent comparison
• eleror Extra-Small — biggest strength: at just 2.3 g per earbud with a flat, no-stem, semi-in-ear shape, it's the more comfortable pick for side sleeping, glasses, and helmet wear.
• eleror Extra-Small — biggest trade-off: no noise control and an open, semi-in-ear fit, so it won't isolate you from the world and it isn't designed for swimming.
• LOBKIN Bone Conduction Swimming — biggest strength: IP68 waterproofing plus 32 GB of built-in memory, so it plays music underwater in MP3 mode with no phone required.
• LOBKIN Bone Conduction Swimming — biggest trade-off: it's a 29 g hook-style headphone with button controls and no noise control, so it's far less discreet and less ideal for lying on your side.
• Who each pick is for: eleror is for small ears and all-day, low-profile wear; LOBKIN is for swimmers and hard-training athletes who need music in the water.
The eleror Z1 is essentially a comfort play. Each earbud weighs 2.3 g and measures roughly 19 x 14 x 10 mm — lighter than a U.S. penny, according to the brand's own framing. That tiny, flat, no-stem design is the whole point: it sits semi-in-ear, resting gently at the opening of your ear instead of burrowing in. For anyone whose ears ache after an hour of normal earbuds, that difference is the reason to look here.
The second thing worth knowing is the fit story. The semi-in-ear shape keeps your ear canal open, so ambient sound passes through. That's genuinely useful for cycling, commuting, and phone calls where you want to hear traffic or a colleague. It also pairs well with glasses and with bicycle or sports helmets, because the flush profile doesn't poke or create pressure points. And because the two earbuds are identical, you can wear either one in either ear without fussing over left and right. Touch controls handle volume, tracks, and calls directly on the bud.
Where it gives ground: there's no noise control at all, so a loud train or a busy gym will bleed through. Battery is 5 hours per charge with about 20 hours total from the case, recharged in roughly 1.5 hours via the case. Water resistance is IPX5 — fine for sweat and light rain, not for swimming or submersion. In my opinion, this is the earbud for the person who prioritizes "I forgot I was wearing them" over isolation and raw bass. If you want thumping low-end or a sealed, quiet listen, skip it. If you sleep on your side, wear a helmet, or have small ears that reject everything else, this is your lane.
The LOBKIN X21 is a different animal entirely. It's a bone conduction headphone, which means it transmits sound through vibrations and leaves your ear canal completely open — no pressure, no deep insertion, no blocked ears. That's the same open-ear philosophy as the eleror, but executed in a hook-style frame rather than a tiny bud.
The headline capability is water. The IP68 rating is engineered for 2+ hours at 10 ft depths, and the built-in 32 GB of memory holds a large local library — the brand cites 8000+ tracks. Critically, Bluetooth doesn't travel through water, so underwater listening happens in MP3 mode with the music stored on the headphones themselves. That's the detail that separates a real swim headphone from a "sweatproof" one: you leave the phone in the locker and the headphones keep playing.
Around that core, the spec sheet is modern and practical. Bluetooth 5.4 handles wireless listening on land, with a noise-canceling microphone for calls. Battery is 10 hours of playback from a 2-hour magnetic charge. The frame is flexible titanium alloy with a skin-friendly soft coating, so it holds its shape and stays put during movement, and it ships with memory foam ear tips plus swim earplugs. At 29 g it's light for a hook-style headphone, but it's still a visible piece of gear on your head, and the controls are physical push buttons rather than touch.
Who should buy it? Swimmers, surfers, and anyone whose workout involves water or heavy sweat, plus runners and cyclists who want open-ear awareness with long battery life. In my opinion, it's also a strong pick for people who simply dislike things inside their ears. Who should skip it? Anyone who wants discreet, invisible listening, or who lies on their side — a hook that wraps behind your ear plus a headband area is not a side-sleeping design. And like the eleror, it has no active noise cancellation, so it's the wrong tool for blocking out a plane cabin.
Side-by-Side: Which Should You Choose?
• Best for side sleeping and pillow comfort → eleror Extra-Small. The 2.3 g flat bud creates no pressure against your ear, which a 29 g hook-style headphone can't match.
• Best for swimming and underwater listening → LOBKIN Bone Conduction Swimming. IP68 plus 32 GB of MP3 storage is a capability the eleror simply doesn't have.
• Best for helmet and glasses wear → eleror Extra-Small. The flush, no-stem profile is designed to sit under helmets without poking.
• Best for the smallest, most discreet fit → eleror Extra-Small. At 19 x 14 x 10 mm per bud, it disappears; the LOBKIN is visibly worn.
• Best for phone-free workouts → LOBKIN Bone Conduction Swimming. Onboard memory means no phone needed at all.
• Best for quick calls and touch convenience → eleror Extra-Small. On-ear touch control for volume and calls is faster to operate mid-activity than push buttons.
• Best for open-ear awareness on land → both. The semi-in-ear eleror and the bone-conduction LOBKIN both let ambient sound in — pick based on water and battery needs, not awareness.
If I had to pick one, I'd buy the LOBKIN Bone Conduction Swimming for its IP68 waterproofing, 32 GB of onboard music, and 10-hour battery — it does things the eleror can't, and it covers swimming, running, and cycling in one device. But I'd only say that if water or long training sessions are part of your routine. If you want near-invisible earbuds for sleeping, helmets, and all-day comfort in small ears, I'd choose the eleror Extra-Small instead. Match the tool to your day and you won't regret either. Check the current price on Amazon before you commit, since both sit in very different budget brackets.
LOBKIN, without question. It carries an IP68 rating engineered for 2+ hours at 10 ft depths plus 32 GB of internal storage for MP3 playback underwater. The eleror is IPX5, which covers sweat and light rain only — not submersion.
That's exactly what it's designed for. Each earbud is 2.3 g with a flat, no-stem, semi-in-ear shape, so it sits flush without creating pressure. The LOBKIN's hook-and-frame design isn't built for side sleeping.
No. Both list noise control as "None." The eleror is semi-in-ear and the LOBKIN is bone conduction, so both intentionally leave your ear open to ambient sound. The LOBKIN does include a noise-canceling microphone for clearer calls, but that's for your voice, not for blocking outside noise.
The LOBKIN, at 10 hours of playback from a 2-hour magnetic charge. The eleror delivers 5 hours per charge with about 20 hours total using its charging case. For a single long session, LOBKIN wins; for topped-up everyday use, the eleror case helps.
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