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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want accurate, isolated studio-grade sound for mixing, tracking and critical listening, choose Audio-Technica ATH-M40x; if you need to keep your ears open and your surroundings audible while you ride, choose Pupabiflor Bone Conduction Headphones. That's the whole decision in one line, and it comes down to what you're actually doing with them. For cycling, the Pupabiflor pair is the one I'd reach for — open ears, wireless freedom, sweat resistance. For everything else, the Audio-Technica wins on fidelity by a wide margin.
• Audio-Technica ATH-M40x — biggest strength: 40 mm dynamic drivers tuned flat, with a circumaural closed-back design that seals around your ears for serious sound isolation and minimal bleed.
• Audio-Technica ATH-M40x — biggest trade-off: It's wired only, with no Bluetooth at all, and the closed seal means you hear almost nothing going on around you.
• Pupabiflor Bone Conduction Headphones — biggest strength: Open-ear bone conduction that leaves your ear canals completely unobstructed, so traffic, bells and voices come through while audio plays via your cheekbones.
• Pupabiflor Bone Conduction Headphones — biggest trade-off: Bone conduction can't match a sealed over-ear driver for bass depth or isolation, and there's no active noise control here.
• Who the M40x is for: Producers, engineers, musicians and anyone doing focused listening at a desk who wants a neutral, accurate reference.
• Who the Pupabiflor is for: Cyclists, runners and gym-goers who want background audio without shutting the world out.
The ATH-M40x is a tool, not a toy. Everything about it points at accuracy: 40 mm dynamic drivers with rare-earth magnets and copper-clad aluminum voice coils, tuned flat across a 15 Hz to 24 kHz range. Impedance sits at 35 ohms and sensitivity at 98 dB, which means it'll run acceptably off a phone or laptop jack without demanding a dedicated amp, though it rewards better sources. The circumaural earcups contour around the ear rather than pressing on it, and that closed-back seal is the reason it isolates so well in loud rooms — and the reason it barely leaks when you track a vocal with a mic live.
Build-wise, it's light at 0.24 kg with an aluminum enclosure and professional-grade earpad and headband material meant to survive daily studio abuse. The 90-degree swiveling earcups let you flip one side off for single-ear monitoring, and the detachable cable with a single-side exit is a genuinely practical touch — snag the cable, replace the cable, not the headphones. You also get a coiled cable, a straight cable, a 6.3 mm snap-on adapter and a carrying case.
Buy it if you're mixing, editing, tracking, practicing an instrument, or you just want an honest wired reference pair that won't flatter bad recordings. Skip it if you need wireless, want to take calls on the move, or need to hear traffic while you're out on a bike. A two-year parts-and-labor warranty backs it up.
The Pupabiflor X3 is built around a single idea: your ears stay open. Instead of pushing sound into your ear canal, it delivers audio through bone conduction via your cheekbones, so ambient sound reaches you uninterrupted. That's not a gimmick for cyclists — it's the entire point. On a bike, hearing a car approach from behind, a bell, or another rider calling out is a safety feature, not a nice-to-have. This is why open-ear designs have become such a common answer to the "best headphone for cycling" question.
The frame is titanium, which keeps it light and flexible enough to hold a secure fit through movement, and the fit is designed to stay put during vigorous exercise. You get Bluetooth 6.0 for wireless freedom, a built-in microphone for calls, and a rated 12 hours of playback per charge — enough for a long ride plus the rest of your day. IPX5 waterproofing means sweat and splashes are handled; it resists moisture during intense workouts rather than surrendering to it. Controls are touch-based. There's no jack and no noise cancelling, and the warranty runs one year.
Buy it if you ride, run, lift or walk outdoors and want music or podcasts without sacrificing awareness. Skip it if you're chasing bass weight, need isolation on a plane or train, or want to do any critical listening. Bone conduction simply doesn't move air the way a 40 mm sealed driver does.
• Best for cycling → Pupabiflor Bone Conduction Headphones. Open-ear awareness plus IPX5 and a secure titanium frame is exactly the combination riders need.
• Best for sound accuracy and mixing → Audio-Technica ATH-M40x. Flat-tuned 40 mm drivers with a closed circumaural seal, no contest.
• Best for noise isolation → Audio-Technica ATH-M40x. The circumaural design blocks outside sound; the Pupabiflor deliberately does the opposite.
• Best for battery life → Pupabiflor Bone Conduction Headphones. 12 hours of wireless playback versus a wired pair that draws nothing at all but tethers you to a device.
• Best for calls on the move → Pupabiflor Bone Conduction Headphones. Built-in mic and Bluetooth 6.0; the M40x has no wireless technology.
• Best for long studio sessions → Audio-Technica ATH-M40x. Lightweight build, professional-grade pads and headband, swiveling cups for one-ear work.
• Best for sweat and weather → Pupabiflor Bone Conduction Headphones. IPX5 waterproofing is designed for exactly this.
• Best for durability and serviceability → Audio-Technica ATH-M40x. Aluminum enclosure, detachable cable, two-year warranty.
If you're specifically after sweatproof true wireless earbuds for cycling, note that neither of these is that category — the Pupabiflor is a bone conduction headband, not in-ear buds, and it's the closer fit for riding of the two.
For cycling, I'd buy the Pupabiflor Bone Conduction Headphones. Open ears on a bike aren't a compromise, they're the correct design — you get 12 hours of playback, Bluetooth 6.0, a mic, IPX5 sweat resistance and a titanium frame that stays put, all while hearing the road. In my opinion it's the more sensible choice for anyone whose main use is outdoor sport.
The Audio-Technica ATH-M40x is the better headphone in absolute sound terms, and if your listening happens at a desk, that's the one I'd recommend without hesitation. But it can't do the job a rider needs. Pick by the activity, not by the spec sheet.
FAQ
No. It's a wired headphone with a 3.5 mm jack and detachable cables — there's no Bluetooth or wireless technology at all. If you need cord-free listening, the Pupabiflor is the wireless option here.
Yes, and that's their main use case. Because they sit outside the ear canal, you keep hearing traffic and your surroundings. The Pupabiflor adds IPX5 waterproofing and a secure titanium frame for exactly that.
The ATH-M40x, clearly. Flat-tuned 40 mm drivers in a sealed circumaural design deliver far more detail and low-end than an open-ear bone conduction driver, which prioritizes awareness over fidelity.
The Audio-Technica ATH-M40x carries a two-year parts-and-labor warranty. The Pupabiflor lists a one-year warranty. If you want to compare what they cost today, check the current price on Amazon for each.
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