We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-29 · 6 min read · Independent comparison
If you want a compact, travel-friendly pair with a folding frame and a lifetime warranty, choose CBGYYWF 2026; if you need the lighter, better-sounding everyday set with a rotating charging case and a real battery figure, choose Monster Open Ear AC390.
• CBGYYWF 2026 — biggest strength: the dual-fold design. The arms fold down so the set tucks into a bag without bulk, which matters if you carry headphones loose in a backpack or commute bag.
• CBGYYWF 2026 — biggest trade-off: the spec sheet never states a playtime number, so you're trusting "ultra-long" without knowing how long that actually is.
• Monster Open Ear AC390 — biggest strength: the battery is spelled out — 8 hours per charge plus 16 hours from the rotating case, 24 hours total — and each bud weighs just 5g.
• Monster Open Ear AC390 — biggest trade-off: the ear-hook shape is fixed. If hooks dig into your ears, there's no folding or adjusting your way out of it.
• Both share: Bluetooth 6.0 and an IPX5 water-resistance rating, so neither is the weak link on splash and sweat protection.
• Buy CBGYYWF 2026 if you want a storable, foldable set for commuting and travel.
• Buy Monster Open Ear AC390 if you want a known playtime figure, a lighter fit, and a charging case you can clip on.
The CBGYYWF 2026 is built around one idea: portability. The dual-fold structure means the arms collapse inward for storage, and that's the feature you'll notice every single day if you're the kind of person who throws headphones in a bag and pulls them out on a train, a plane, or a break room. It's a small thing on paper and a big thing in practice, because bulky headphones are the ones people leave at home.
On paper it also leans on Bluetooth 6.0 and a claimed ultra-long playtime, noise isolation for blocking ambient sound, and an IPX5 rating that covers rain, sweat, and splashes. The ABS enclosure and on-ear placement suggest a lightweight plastic build rather than anything premium. Notably, the product information lists a lifetime warranty, which is unusual at this tier and worth knowing about if durability long-term is your worry.
Who should buy it: commuters and travelers who want something that folds flat, anyone who wants noise isolation on planes and in offices, and shoppers who value the folding mechanism plus that warranty over a published battery number. Who should skip it: if you need to know exactly how many hours you get before you buy, or you want a charging case with its own reserve power, this isn't the set that answers those questions. Also skip it if you want color options beyond the listed black and white.
The AC390 is the more conventional of the two, and that's a compliment. Each earbud weighs 5g and hangs on a soft silicone ear hook, so the design goal is all-day comfort with nothing pushed into your ear canal. Monster pairs that with a 13mm PU titanium diaphragm driver (listed as an 18mm audio driver size, dynamic driver type) and Dynamic Noise Cancellation for calls, so the pitch here is sound quality first and fit second.
The battery story is the clearest part of the spec sheet: 8 hours on a charge, 16 more from the rotating charging case, 24 hours total, with an 8-hour charge time listed. The case rotates and includes a lanyard, which is a genuinely handy detail if you clip things to a bag strap. Controls run through touch and voice, including Siri, and noise control is listed as environmental noise cancellation rather than active isolation — worth understanding before you buy, because it behaves differently from the isolation approach on the CBGYYWF set.
Who should buy it: runners, gym-goers, and long-shift workers who want a light open-ear fit and a known 24-hour total. Who should skip it: if you prefer a foldable, storable frame, or you want on-ear isolation rather than an open-ear design that deliberately lets ambient sound in. The open-ear shape is the point — if you want to shut the world out, this isn't the tool.
Side-by-Side: Which Should You Choose?
• Best for portability and storage → CBGYYWF 2026. The dual-fold frame is the single most practical difference between these two.
• Best for light, all-day comfort → Monster Open Ear AC390. 5g per bud with a soft silicone hook.
• Best for noise blocking → CBGYYWF 2026. Noise isolation is a listed feature; the Monster set uses environmental noise cancellation aimed mainly at calls.
• Best for sound detail on paper → Monster Open Ear AC390. A 13mm PU titanium diaphragm driver is a specific, named driver; CBGYYWF lists virtual bass but no driver size.
• Best for carrying the case → Monster Open Ear AC390. The rotating case has a lanyard.
• Best for long-term peace of mind → CBGYYWF 2026. A lifetime warranty is listed.
• Best waterproofing → a tie. Both are IPX5, so both handle sweat, splashes, and light rain and neither is built for swimming.
In my opinion, the Monster Open Ear AC390 is the better buy for most people, and it comes down to information: you know the playtime (24 hours total), you know the weight (5g per bud), and you know the driver (13mm PU titanium). That's a set you can plan around. I'd pick the CBGYYWF 2026 only if folding storage is a daily priority for you, or if that listed lifetime warranty is what tips it. Both are IPX5, so neither wins on water protection. Check the current price on Amazon before you commit — that's the one variable that can flip this call.
are headphones waterproof
No — and neither of these is an exception. Both the CBGYYWF 2026 and the Monster Open Ear AC390 carry an IPX5 rating, which means resistance to sweat and splashes and light rain, not submersion. Don't swim or shower in either one.
are headphones water resistant
Yes, and in this matchup both are. IPX5 on both models covers sweat during workouts, splashes, and light rain, so either set is fine for the gym or a commute in bad weather. Just note that IPX5 is a splash rating, not a waterproof one.
By the specs, the Monster Open Ear AC390: 8 hours per charge plus 16 hours from the charging case for 24 hours total. The CBGYYWF 2026 advertises ultra-long playtime but doesn't publish a number, so it's not a fair comparison on paper.
Neither guarantees a universal fit, but the Monster AC390's 5g silicone ear hooks are designed to suit a range of ear shapes for extended wear. The CBGYYWF 2026 uses an on-ear, ear-hanging design, which suits some ears better than hooks and others worse — fit preference is the deciding factor here.
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