How We Research
Updated: 2026-09-21 · 7 min read · Independent comparison
If you want a tiny adapter that lets you keep using your favorite 0.78 mm two-pin IEMs with a 0.75 mm cable, choose okcsc 0.78; if you need actual invisible wireless earbuds built for sleeping on your side, choose goazzzl Sleep Earbuds.
• okcsc 0.78 — biggest strength: a 0.78 mm male to 0.75 mm female two-pin adapter made of high-purity OFC, so you can bridge two pin standards without buying a whole new cable.
• okcsc 0.78 — biggest trade-off: it is a passive connector, not a listening device. It makes no sound on its own and does nothing for you unless you already own 0.78 mm earbuds and a 0.75 mm cable.
• goazzzl Sleep Earbuds — biggest strength: a compact, ergonomic, near-invisible true wireless design with soft silicone tips and caps, explicitly built to stay put for side sleepers.
• goazzzl Sleep Earbuds — biggest trade-off: it is a Bluetooth earbud, so it needs charging and pairing, and its sound isolation approach will not match a sealed, wired IEM setup.
• Pick okcsc 0.78 if you are an IEM tinkerer chasing a specific cable-and-earbud combination.
• Pick goazzzl Sleep Earbuds if you want something to fall asleep to, discreetly, without a wire running across your pillow.
Let's be blunt about what this thing is. The okcsc 0.78 is a pair of mini headphone adapters — 0.78 mm two-pin male on one end, 0.75 mm two-pin female on the other. That's it. It is roughly 0.19 inches in size and weighs about 0.3 grams, so it's the kind of part you could lose between your fingers if you're not careful. The color is clear, and you get one pair.
What it does best is solve a very specific annoyance. Two-pin IEM connectors come in 0.75 mm and 0.78 mm flavors, and they are not interchangeable by default. If your earbuds use one standard and the cable you want uses the other, this adapter sits in the middle and makes the connection work. okcsc lists compatibility with a long roster of models — KZ BA10, AS10, ZS10, ZSR, ZST, ZSN, ZSN PRO, ZSN PRO X, ZSTX, ZAX, ASF, ASX, AS16, ED12, ES3, ES4, EDX, plus TRN V10 and V20 and MOONDROP — which tells you this is aimed squarely at the budget-to-mid chi-fi crowd that swaps cables constantly.
The material matters here. okcsc uses high-purity OFC (oxygen-free copper) in the adapter, and the brand frames the whole point as conversion "without compromising on sound quality." Whether you hear a difference is your call, but the intent is clearly lossless-style signal pass-through rather than a cheap resistive joint. The brand also notes that some adapter models can be used with a cable puller to avoid damaging the headset — a small but genuinely useful detail if you've ever yanked a delicate two-pin socket.
Who should buy it: someone who already owns 0.78 mm two-pin earbuds and either has or wants a 0.75 mm cable, and who cares about keeping the chain clean. Who should skip it: anyone who doesn't own a detachable-cable IEM, anyone expecting sound on its own, and anyone who wants a simple one-piece solution rather than another tiny part in the chain. If you're the type who hates dongles and adapters, this will annoy you. The warranty is listed at 60 days, so factor that into how you think about the risk of a small, easily lost component.
The goazzzl Sleep Earbuds are a completely different animal. These are true wireless earbuds — model SK26, in beige — and the entire design brief is "make yourself invisible and comfortable enough to sleep in." The brand calls them invisible earbuds with a compact, ergonomic body that sits naturally inside the ear, and the lightweight build is pitched at long wear: daily use, travel, relaxation.
The sleep angle is the real story. goazzzl specifically emphasizes ultra-soft silicone eartips and caps that give a snug but gentle fit and stay secure "even for side sleepers." That's the detail that separates a sleep bud from a normal bud. If you sleep on your side, a standard earbud jams into your ear canal and your pillow simultaneously, and you feel it within ten minutes. A short, soft, low-profile body is the fix, and that's what this design is chasing.
Functionally, they're modern wireless earbuds. One-step auto pairing means you pull them out of the charging case and they reconnect to your last device automatically — no menu diving. Touch controls handle playback, volume, calls, and voice assistants. Compatibility covers iOS, Android, Mac and most Bluetooth devices, so this isn't locked to one ecosystem. On audio, goazzzl points to an advanced speaker and acoustic cavity design that delivers clear, balanced sound while reducing sound leakage — which matters at night, because leaking audio from your earbuds is exactly what wakes the person next to you. They're also IPX5 waterproof, so sweat, light rain and workouts won't kill them. Noise control is listed as sound isolation, meaning the seal does the work rather than active cancellation.
Who should buy it: side sleepers, light sleepers who want something to drift off to, people with small ear canals who find normal buds too bulky, and anyone who wants a discreet bud for podcasts, audiobooks or white noise at night. Who should skip it: anyone who wants wired, zero-latency, no-charging audio; anyone who needs strong active noise cancellation; and anyone who wants a full-size soundstage for critical listening. These are comfort-first earbuds, not reference monitors.
• Best for sleep and side sleeping → goazzzl Sleep Earbuds. Soft silicone tips, a low-profile body and a design explicitly built for nighttime wear.
• Best for fixing a cable mismatch → okcsc 0.78. It exists for exactly one job: 0.78 mm male to 0.75 mm female two-pin conversion.
• Best for cable-swapping IEM owners → okcsc 0.78. The compatibility list covers a huge range of KZ, TRN and MOONDROP models.
• Best for wireless freedom → goazzzl Sleep Earbuds. Bluetooth with one-step auto pairing, touch controls and iOS/Android/Mac support.
• Best for keeping your existing wired setup intact → okcsc 0.78. No battery, no pairing, no charging case, just a passive OFC adapter.
• Best for workouts and travel audio → goazzzl Sleep Earbuds. IPX5 waterproofing is the deciding factor here.
• Best for discretion → goazzzl Sleep Earbuds. The invisible, in-ear design is the whole point.
• Best for people who hate charging things → okcsc 0.78. It never needs a battery because it doesn't have one.
In my opinion, these two products barely compete — they solve unrelated problems, so the honest answer is that most readers should pick based on what's actually missing from their life. If you're an IEM hobbyist stuck with a 0.78 mm earbud and a 0.75 mm cable, the okcsc 0.78 is the cheap, clean fix and I'd grab it without thinking twice. But if you landed on this comparison because you want to fall asleep listening to something, the goazzzl Sleep Earbuds are the one I'd buy: the side-sleeper fit, soft silicone tips, auto pairing and IPX5 rating are all aimed directly at that use case. The adapter can't play a note; the earbuds can. For a general shopper, that settles it.
No. It's a pair of two-pin headphone adapters — 0.78 mm male to 0.75 mm female — used to connect 0.78 mm earbuds to a 0.75 mm cable. It produces no sound on its own and has no battery.
That's the design intent. goazzzl uses ultra-soft silicone eartips and caps with a compact, low-profile body meant to stay secure and comfortable for side sleepers through the night.
I don't quote prices here because they change. Use the "Check latest price on Amazon" button on this page to see the current figure for whichever one you're considering — and remember these are two very different product categories, so the numbers aren't really comparable anyway.
They aren't comparable in the usual sense. The goazzzl Sleep Earbuds have speakers, an acoustic cavity design and sound isolation. The okcsc 0.78 has no drivers at all — its job is to pass your existing IEM's signal through with OFC conductors so your earbuds and cable can finally connect.
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