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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-03 · 7 min read · Independent comparison
• Amazon Renewed TREBLAB Z2 — biggest strength: a sport-first build with IPX4 sweatproofing, hybrid active noise cancelling, aptX audio from 40mm neodymium-backed drivers, and a foldable frame that ships with a hard carrying case.
• Amazon Renewed TREBLAB Z2 — biggest trade-off: it is a renewed unit backed by a 90-day limited warranty, so you are buying a restored pair rather than a brand-new one, and its 35-hour battery is shorter than the FJHBL's.
• FJHBL Headphones — biggest strength: up to 60 hours of playtime with ANC off (roughly 40 hours with ANC on), a rated noise reduction of up to 48dB, Hi-Res Audio certification, and a detachable boom mic that works wired or wirelessly.
• FJHBL Headphones — biggest trade-off: the spec sheet lists no IP rating, no codec detail, and no stated charge time, so it reads more as a general-purpose desk, travel and gaming headset than a gym companion.
• Who each pick is for: pick the TREBLAB Z2 if you train hard and want sweat resistance plus a travel case; pick the FJHBL if you want long battery, spatial audio and a boom mic for calls.
The TREBLAB Z2 is built around movement. Its 40mm dynamic drivers sit behind a 32-ohm impedance and a 20Hz–20kHz frequency range with 93dB sensitivity, and the sound is fed over Bluetooth 5.0 with aptX. In plain terms, that combination is aimed at wireless listening from a phone or tablet where the source can carry the higher-quality aptX stream. A 3.5mm jack is also on board, so you can go wired when the battery runs out or when you want zero latency.
What really shapes the ownership experience is the sport angle. The enclosure is leather and plastic, the earpieces are oval and over-ear, and the pads are memory foam with ultra-soft materials — a setup designed to stay put during running, jumping and lifting rather than to sit still on a desk. IPX4 sweatproofing matters here: it is splash and sweat resistance, not full waterproofing, so it handles a hard workout but not a swim or a downpour. T-Quiet active noise cancelling cuts external noise, cVc 6.0 handles call clarity, and the button controls keep things simple with gloves on. Battery life is rated at 35 hours with a 3-hour charge time, and a short 5-minute top-up is described as good for about 2 hours of playback. The whole thing folds and travels in a rubberized-plastic case measuring roughly 6.5 x 3.54 x 8.07 inches, and at 9.03 ounces it is a substantial, full-size pair.
Buy it if you want one pair for the gym, the commute and the flight, and you value a physical case plus a wired fallback. Skip it if you need the longest possible runtime between charges, you rely on a boom mic for meetings, or you would rather not deal with a renewed unit and its 90-day limited warranty. Also note the age range is listed as adult, and the box includes the cable, ear cushions and a user manual.
The FJHBL M12 is the endurance and versatility play. Its headline number is 60 hours of continuous playtime with ANC off, dropping to roughly 40 hours with ANC on — that is the kind of runtime that gets you through a week of commuting, a long-haul flight, or several days of work-from-home calls without hunting for a cable. Noise cancelling is rated to reduce ambient noise by up to 48dB, which is the sort of figure you want on a plane, a train or a noisy open office.
The audio side leans on 40mm large-aperture dynamic drivers paired with Hi-Res Audio certification, and the tuning is described as crisp highs and deep bass. There is also spatial sound for a 360-degree effect, which is aimed squarely at movies and gaming rather than at a workout playlist. The detachable boom mic is the detail that separates it from most everyday headphones: it is high-sensitivity, designed for clear calls and in-game chat, and it pops off when you want a cleaner look for the street. It supports both wired and wireless use, so you are not stranded when the battery eventually empties. Around your head, the design uses ultra-soft breathable cushions and an adjustable lightweight headband, and the frame folds flat into a protective carrying case for a bag or backpack.
Buy it if battery life, noise reduction depth and call clarity top your list, and you want one headset that covers commuting, gaming and video calls. Skip it if you need a stated sweat or water rating for hard training, you want the specific aptX codec and low-latency gaming mode detailed on the spec sheet, or you want published charge-time figures. The sheet also does not list impedance, frequency response, weight or a specific Bluetooth version, so if those numbers matter to you, this one is a blank.
• Best for battery life → FJHBL Headphones. 60 hours with ANC off versus 35 hours on the TREBLAB Z2.
• Best for workouts and sweat → Amazon Renewed TREBLAB Z2. IPX4 sweatproofing plus a secure oval over-ear fit and memory foam pads.
• Best for calls and gaming → FJHBL Headphones. A detachable high-sensitivity boom mic and spatial sound for a 360-degree effect.
• Best for travel with a case → either, with a caveat. The TREBLAB ships with a rubberized-plastic case at a stated size; the FJHBL folds flat into a protective case.
• Best for codec and latency detail → Amazon Renewed TREBLAB Z2. Bluetooth 5.0 with aptX and a stated 65ms gaming-mode latency.
• Best for deep noise reduction → FJHBL Headphones, on paper, with ANC rated up to 48dB.
• Best for wired backup → FJHBL Headphones, since the mic and wired mode are part of the design; the TREBLAB also offers a 3.5mm jack for wired listening.
• Best for buyer confidence → depends on your risk appetite. The TREBLAB is renewed with a 90-day limited warranty; the FJHBL is a new unit, though the sheet only lists "1" under warranty description.
In my opinion, the FJHBL Headphones are the stronger all-rounder for most people. Sixty hours of playtime, an ANC rating up to 48dB, Hi-Res Audio, spatial sound and a detachable boom mic cover commuting, calls, movies and gaming in one package, and that is a lot of ground for a single pair to hold.
I would only steer you to the Amazon Renewed TREBLAB Z2 if your priority is training. The IPX4 rating, memory foam pads, aptX audio and 65ms gaming mode make it the more purposeful sports design, and the included case is a genuine travel convenience. If sweat and movement define your listening, that is the one I would buy. Otherwise, go FJHBL.
Either way, check the current price on Amazon before you commit, since that is the one number that can flip this call.
what is 40mm driver in headphones
A 40mm driver is the diameter of the speaker unit inside each earcup — 40 millimeters across. Both the TREBLAB Z2 and the FJHBL M12 use 40mm dynamic drivers, which is a common size for full-size over-ear headphones because it moves enough air for solid bass without making the cups bulky.
what are 40mm drivers in headphones
They are the moving speaker elements that convert the electrical signal into sound. On the TREBLAB Z2 they are neodymium-backed and paired with aptX over Bluetooth 5.0; on the FJHBL they are described as large-aperture drivers paired with Hi-Res Audio certification. Same size, different supporting electronics.
which driver is best for headphones
There is no single best driver size — it depends on tuning and the rest of the chain. A 40mm dynamic driver is a well-rounded choice for over-ear headphones, and both of these models rely on it. What separates them is everything around the driver: codec support, ANC strength, battery and mic design.
is 40mm driver good for headphones
Yes, 40mm is a good, mainstream size for over-ear headphones. It is large enough for convincing bass and detail while keeping the earcups wearable for long sessions, which is exactly why both the TREBLAB Z2 and the FJHBL M12 use it.
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