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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-02 · 6 min read · Independent comparison
• GREYOLK's biggest strength: a genuine IP68 waterproof rating plus 32GB of built-in MP3 memory — it keeps playing underwater with no phone or Bluetooth signal involved.
• GREYOLK's biggest trade-off: it's a single-piece neckband-style headphone with no charging case, and Bluetooth simply doesn't work underwater, so you have to switch modes manually. I also see the spec sheet list Bluetooth 5.4 in the title but 5.3 in the style details, so treat the exact version as a bit ambiguous.
• MKKLTUOP's biggest strength: up to 12 hours of continuous playtime per charge, topped up by a charging case that adds up to 48 more, with a Type-C case that refills in about an hour.
• MKKLTUOP's biggest trade-off: IPX7 only — sweat, splashes and light rain, but explicitly not swimming or full immersion. Warranty is also short at 3 months.
• Pick GREYOLK if your priority is swimming, snorkeling or any activity where you get fully submerged.
• Pick MKKLTUOP if your priority is all-day running and commuting audio with awareness of traffic around you.
The GREYOLK set is built around one idea: keep audio going when the water closes over your head. The IP68 rating is the headline. That's full waterproofing, and the brand describes it as suitable for swimming, snorkeling, fishing and boating. The catch is that Bluetooth can't travel through water, so once you're submerged you're on the built-in MP3 player, not your phone.
That's why the 32GB of internal storage matters so much here. You load files over the magnetic charging cable — the headphones show up as a memory disk on your computer — and you can carry a huge library in MP3, WMA, WAV, APE or FLAC. Switching between Bluetooth and MP3 mode is a double-click on the power button. For running, the open-ear bone conduction design means you hear traffic and footsteps around you, which is exactly what I'd want on a road route. At 32 grams with a wraparound titanium frame, it's designed to stay put through hard training, and you can wear it with a swim cap, goggles and earplugs.
Buy it if you swim or snorkel and want music without leaving a phone on the poolside, or if you want one headset that covers both the pool and the pavement. Skip it if you mostly want casual all-day listening with a pocketable case — there's no case here, and the 8-hour battery from a 1.5-hour charge is decent but not remarkable. The 2-year after-sales service is a genuine plus.
MKKLTUOP Open Ear Clip: Who It's For
The MKKLTUOP A51 is a very different animal. These are true wireless open-ear earbuds with ear hooks, sitting outside the ear canal so you stay aware of what's happening around you. The dual-bevel ear hooks are designed for a secure fit during workouts — the kind of thing you want when you're mid-run and don't want to stop and re-seat an earbud.
Sound comes from 16.3mm dynamic drivers, and the brand leans on clear calls thanks to the built-in mic. Touch controls handle playback with a tap. Bluetooth 5.4 is listed, which should mean fast pairing and low latency. On the water front, IPX7 handles sweat, splashes and light rain — fine for running, the gym and commuting, but the brand is explicit that it isn't for swimming, showering or full immersion.
Buy it if running, fitness and office use are your main scenarios and you want long battery life with a case you can pocket. Skip it if you swim — IPX7 won't survive that, and the 3-month warranty is far shorter than GREYOLK's.
• Best for swimming → GREYOLK Swimming Headphones. IP68 plus 32GB of on-board MP3 memory is the only combination here that works underwater.
• Best for running with traffic awareness → either, but for different reasons. GREYOLK's bone conduction open-ear design keeps you aware without anything in your ears; MKKLTUOP's ear-hook open design does the same with a more secure athletic fit.
• Best for battery life → MKKLTUOP Open Ear Clip. 12 hours per charge plus a case adding up to 48 more beats GREYOLK's 8 hours.
• Best for carrying your own music library offline → GREYOLK Swimming Headphones. 32GB, roughly 6,000 songs, and multiple lossless-ish formats.
• Best for calls and everyday use → MKKLTUOP Open Ear Clip. Built-in mic, 16.3mm dynamic drivers and touch controls suit office and commute use better.
• Best for charging convenience → MKKLTUOP Open Ear Clip. A Type-C case that fills in about an hour and shows battery on an LED display.
• Best for long-term peace of mind → GREYOLK Swimming Headphones. A 2-year after-sales service versus 3 months on the MKKLTUOP.
• Best for durability in wet conditions → GREYOLK Swimming Headphones. IP68 is a higher waterproof rating than IPX7, and it's rated for full immersion.
In my opinion, the right pick depends entirely on whether water is part of your routine. If you swim — even occasionally — I'd take the GREYOLK Swimming Headphones. IP68, 32GB of offline music and a 2-year service window make it the more versatile and more durable choice, and it still handles running well thanks to the open-ear bone conduction build. If you never swim and want the longest battery life, a charging case and a lighter everyday experience for running, fitness and the office, I'd take the MKKLTUOP Open Ear Clip. For most buyers who want one pair of Bluetooth headphones for running, GREYOLK edges it on versatility.
There's no single answer — it depends on your conditions. If you run near water or swim as well, the GREYOLK Swimming Headphones fit best with IP68 waterproofing, an open-ear bone conduction design and a titanium wraparound frame. For dry-land running with maximum battery life, the MKKLTUOP Open Ear Clip's 12-hour playtime and ear-hook fit are the stronger match.
If you specifically want earbuds with a charging case, the MKKLTUOP Open Ear Clip is the one to look at here: true wireless, ear hooks for a secure fit, IPX7 sweat resistance, 12 hours per charge and a case adding up to 48 more. The GREYOLK is a single-piece headphone rather than a case-based earbud, so it's a different format.
No. The brand states IPX7 covers sweat, splashes and light rain only, and it is not designed for swimming, showering or full water immersion. For swimming you need the GREYOLK's IP68 rating, and remember Bluetooth doesn't work underwater — you'd switch to its built-in MP3 mode.
GREYOLK gives up to 8 hours of playback or talk time from a 1.5-hour charge via its 150mAh battery. MKKLTUOP gives up to 12 hours of continuous play per charge, with the charging case adding up to 48 more hours and up to 60 hours of standby, refilling in about an hour over Type-C. MKKLTUOP wins on total runtime.
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