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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want an open-ear pair that keeps you aware of traffic and your surroundings while you run, choose Monster Open Ear AC336; if you need to shut the world out on a long flight or in a noisy office, choose Wentronic Y03.
• Monster Open Ear AC336 — biggest strength: a genuinely open-ear hook design with an IPX6 water-resistance rating, so sweat, rain and long training sessions are not a problem.
• Monster Open Ear AC336 — biggest trade-off: no active noise cancellation at all, and total battery life tops out at 21 hours with the case.
• Wentronic Y03 — biggest strength: active noise cancellation plus a 48-hour battery figure (32 hours with ANC on), which is a completely different league for long listening sessions.
• Wentronic Y03 — biggest trade-off: it is a full over-ear headphone in green plastic, so it is bulky, warm on the ears in summer, and does nothing to keep you aware of your surroundings.
• Pick Monster Open Ear AC336 if you run, cycle or lift and want your ears open to the world.
• Pick Wentronic Y03 if you commute, fly or study and want the world switched off.
The AC336 is built around one idea: never block the ear canal. The hook-style earpiece sits outside your ear rather than sealing it, and Monster leans on a 13mm dynamic driver and Qualcomm apt-X HD decoding to make up for the fact that you are not getting a sealed, bass-heavy listen. The numbers on the sheet are 20 Hz to 20,000 Hz with 140 ohm impedance — a fairly high impedance figure for a wireless earbud, which in practice usually means the tuning is not trying to be a bass cannon. That tracks with an open design.
The comfort story is the other half of the pitch. Monster describes a shape-memory hardshell material that holds its shape over long wear, and the whole package is light — the item weight listed is 0.14 kg including the case. Bluetooth 6.0 is the headline connectivity spec, with a claimed 33-foot range, auto power-on when you lift them out of the case, and touch controls on the earpiece itself. Battery is 7 hours on a charge at 50–60% volume, 21 hours total with the case, and USB-C fast charging gives you about an hour of playback from a 10-minute top-up. IPX6 covers sweat and rain, not swimming.
So who is this for? Runners, cyclists, hikers and gym people who need to hear a car, a fellow rider or a gym announcement while they train. Anyone who finds sealed earbuds itchy or painful after an hour. Anyone who wants a quick-charge top-up before heading out the door. Who should skip it? If your main use is a noisy train carriage or an open-plan office, the AC336 has no noise cancellation whatsoever — the sheet lists noise control as "None." It is also not the pick for someone who wants deep, isolating bass.
The Y03 is the opposite philosophy. It is a circumaural over-ear headphone — the cups fully enclose your ears — with active noise cancellation designed to flatten airplane engines, subway rumble and office chatter. That is the feature doing the heavy lifting here, and it is the single biggest reason someone would pick this over a pair of open earbuds.
The rest of the sheet reads like a long-haul travel kit. Bluetooth 5.4 for a stable, low-latency connection. A rated 48 hours of playback per charge, dropping to 32 hours with ANC switched on — still enormous. Six EQ modes (Pop, Rock, Jazz, Classical, Electronic, Normal) switchable straight from the on-headphone buttons, no app needed, which is a nice touch if you hate pairing apps. Wentronic also claims large dynamic drivers with high-sensitivity diaphragms for detailed vocals and controlled bass. Comfort comes from protein-leather ear cushions and an adjustable headband, with breathable materials to stop your ears cooking during long sessions. Note the 3.5mm jack — you can go wired if the battery dies or if you want zero latency.
Who is this for? Commuters, students, frequent flyers and anyone who works in a noisy space and wants a quiet bubble. People who genuinely wear headphones for eight hours a day and care about battery anxiety. Who should skip it? Runners and cyclists — an over-ear headphone with ANC is the wrong tool when you need to hear traffic. And if you hate the feeling of cups clamped over your ears in warm weather, the open-ear design will suit you better.
Side-by-Side: Which Should You Choose?
• Best for staying aware of your surroundings → Monster Open Ear AC336. It does not seal or cover your ears at all, which is exactly what you want on a road run or a busy bike path.
• Best for maximum battery life → Wentronic Y03. 48 hours, or 32 with ANC on, versus 21 hours total on the Monster with its case.
• Best for sweat and rain → Monster Open Ear AC336. IPX6 water resistance is a spec the Y03 sheet does not claim.
• Best for long wear comfort in warm conditions → Monster Open Ear AC336. Open ear means no cups trapping heat; the Y03 relies on breathable materials to manage the same problem.
• Best for flights, trains and open-plan offices → Wentronic Y03. This is the exact scenario the ANC and 48-hour battery were designed for.
• Best for quick top-ups → Monster Open Ear AC336. USB-C fast charging gives roughly an hour of playback from a 10-minute charge.
• Best for wired fallback and EQ tinkering → Wentronic Y03. A 3.5mm jack plus six on-board EQ modes cover both.
• Best for a secure, forget-it's-there fit → Monster Open Ear AC336. The hook design and shape-memory material are built around staying put without pressure.
In my opinion, the honest answer is that these two barely compete — they solve opposite problems. If I had to buy one for myself and my use was commuting, working or flying, I would buy the Wentronic Y03. Active noise cancellation plus that battery figure is a combination the Monster cannot answer, and the 3.5mm jack and six EQ modes make it more flexible for everyday listening. I would only reach for the Monster Open Ear AC336 if my priority was training outdoors with my ears open to traffic and sweat-proofing — in which case the Y03 is the wrong product entirely. Decide which of those two people you are, and the choice makes itself.
No. The spec sheet lists noise control as "None." The AC336 uses an open-ear design and ENC for calls, which filters background noise on your voice during a call — it does not cancel noise for you while listening.
Wentronic rates it at 48 hours of continuous playback per charge, dropping to 32 hours when active noise cancellation is switched on. That is roughly double the Monster's 21-hour total with its charging case.
Yes. It has a 3.5mm jack alongside Bluetooth 5.4, so you can plug in directly if the battery runs out or you want a wired, zero-latency connection. The Monster AC336 has no headphone jack — it is wireless only.
The Monster Open Ear AC336, without question. It is IPX6 water resistant, sits open so you can hear traffic, and hooks over the ear instead of clamping around it. The Y03 is an over-ear headphone with ANC — great for a plane, wrong for a pavement.
Both listings change over time, so check the current price on Amazon using the button on this page before you decide. Price is not part of this comparison — the design and feature differences above are what should drive your choice.
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