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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want Hi-Res certified sound with EQ presets and a tangle-free flat cable, choose JBL Tune 310C; if you need two pairs of USB-C earbuds with a mic and remote for your iPhone 15 or newer, choose IIOZO 2. That's the honest short version. Both are wired in-ear headphones with USB-C or wired connectivity, and both are built for the same basic job: plug in, press play, no charging, no pairing. The split comes down to tuning control versus quantity and phone compatibility.
• JBL Tune 310C — biggest strength: Hi-Res certified audio with JBL Pure Bass, plus a three-button remote that also switches between Default, Bass and Vocal EQ presets. That's sound shaping you can do without opening an app.
• JBL Tune 310C — biggest trade-off: One pair in the box, and USB-C only, so you have to confirm your device actually takes USB-C audio before buying.
• IIOZO 2 — biggest strength: A 2-pack, Apple MFi certification, and a 36-month warranty. Two pairs means one for the bag and one for the desk.
• IIOZO 2 — biggest trade-off: No frequency range or driver spec is published, and there's no EQ control — just a remote with press-once, press-twice, press-three commands.
• Who JBL Tune 310C is for: buyers who care about the sound itself and want preset tuning on the cable.
• Who IIOZO 2 is for: iPhone 15/16/17 and USB-C Android owners who want a spare pair and long warranty coverage.
The Tune 310C is JBL's wired in-ear model, and the spec sheet tells you where the effort went. It's Hi-Res certified, runs a dynamic driver across a 20 Hz – 20,000 Hz frequency range, and carries 16 ohm impedance. Low impedance like that is an easy load for a phone or laptop to drive, so you get usable volume without a dongle amp. The whole thing weighs 14.3 g, which is light enough that you forget it's there.
The feature I'd actually use daily is the three-button remote. It handles play/pause, volume, and calls through the built-in mic — but it also cycles EQ presets: Default, Bass, or Vocal. That's rare at this tier. If you switch between podcasts and bass-heavy music, you can tune the headphones to the content instead of living with one fixed sound. JBL leans on its Pure Bass tuning here, so the Bass preset is the one I'd expect most people to leave on.
The flat cable is the small thing that matters more than it sounds. Flat cables resist tangling in a bag or a jacket pocket, and that's the difference between grabbing your headphones and untangling them. Build is plastic, black, rounded-tip in-ears, wired connection, with a 3.5 mm jack listed alongside the USB-C connectivity in the specs — so double-check which version you're actually plugging into before you commit.
Skip it if: you need two pairs, you want the longest warranty, or you'd rather have earbuds explicitly certified for iPhone.
IIOZO 2: Who It's For
The IIOZO 2 plays a different game. It's sold as a 2-pack of USB-C wired earbuds, and the headline claim is Apple MFi certification — meaning they're built and tested for the USB-C port on iPhone 15, 16 and 17 series, plus iPad Pro. The listing also names Galaxy S20 through S26 Ultra and Pixel 7 through 10. If you've ever plugged cheap USB-C earbuds into a newer iPhone and gotten nothing, you know why that certification line matters.
The remote is simple and clearly documented: press once for play/pause, twice for next track, three times for previous track. There's a microphone for calls, and the design leans on advanced noise reduction plus "professional-grade tuning" with main and secondary sound holes for a 360° surround presentation. Take the marketing language for what it is, but the two-chamber acoustic design is a real approach used to widen the perceived soundstage in small earbuds.
What's missing from the sheet is just as telling. There's no published frequency range, no driver type, no impedance figure. So I can't tell you how the IIOZO 2 measures up on paper against the JBL's Hi-Res certification — only that it doesn't claim it. The housing is ABS plastic in white, in-ear shape, wired, with no wireless technology at all.
The strongest practical argument is the bundle math and the warranty. Two pairs plus a 36-month worry-free warranty and 24/7 support is a lot of coverage for a set of wired earbuds. Wired earbuds die from cable strain at the plug, not from drivers failing. Having a second pair in the drawer means you're never stuck.
Buy it if: you own a USB-C iPhone or a recent Galaxy/Pixel, you want a backup pair, or you want the safety net of a three-year warranty.
Skip it if: you want published audio specs and EQ control, or you need a 3.5 mm option.
• Best sound credentials → JBL Tune 310C. Hi-Res certified, 20 Hz – 20,000 Hz range, dynamic driver, 16 ohm.
• Best sound control → JBL Tune 310C. Default, Bass and Vocal EQ presets straight off the three-button remote.
• Best for iPhone 15/16/17 → IIOZO 2. Apple MFi certification is the whole point of that model.
• Best for cable management → JBL Tune 310C. The flat tangle-free cable is a real daily-use advantage.
• Best value in the box → IIOZO 2. Two pairs instead of one, plus a 36-month warranty.
• Best for hands-free calling on either platform → a tie. Both have a mic and a remote with call handling.
• Best for travel and commuting → JBL Tune 310C. Lighter, tangle-resistant, and tunable when the environment changes.
• Best for a household with two USB-C devices → IIOZO 2. One pack covers two people or two bags.
In my opinion, the JBL Tune 310C is the one I'd buy for myself. The reason is concrete: it's the only one of the two that publishes real audio specs — Hi-Res certification, a 20 Hz – 20,000 Hz range, a dynamic driver — and it's the only one that lets me change the sound with EQ presets on the cable. That's a headphone I can adapt to what I'm listening to.
I'd recommend the IIOZO 2 without hesitation to a different buyer: someone on a USB-C iPhone who wants two pairs and a three-year warranty, and who doesn't need spec sheets or EQ. It's the safer, more practical pick for that person. Just check the current price on Amazon for whichever one you're leaning toward — that's the last variable I can't answer for you from the specs alone.
how to wired headphones work
Wired headphones turn an electrical audio signal from your device into sound through a small driver inside each earpiece. The signal travels down the cable from the plug — USB-C on both of these models — into the driver, which moves air and produces the sound you hear. No battery, no pairing, no charging: the device supplies both the signal and the power.
how to use wired headphones with iphone
It depends on the iPhone's port. The IIOZO 2 is built for the USB-C port on iPhone 15, 16 and 17 series and carries Apple MFi certification for that connection, so it plugs straight in. Older iPhones with a Lightning port need a different connection entirely, and the JBL Tune 310C specs list USB-C and a 3.5 mm jack — check which your device accepts before buying.
how to fix wired headphones no sound
Start with the connection: unplug and reseat the cable, and confirm your device actually supports audio over USB-C, since not every USB-C port does. Then check the obvious things — volume, the correct output device selected, and whether the remote's play/pause button is stuck. If one earpiece is silent, the usual culprit is cable damage near the plug, which is exactly the failure a second pair like the IIOZO 2's covers you against.
how to wired headphones
Using wired headphones is simple: plug the connector into a compatible port, press play, and use the inline remote for volume, tracks and calls. On the JBL Tune 310C, the three-button remote also cycles Default, Bass and Vocal EQ presets. On the IIOZO 2, press once for play/pause, twice for next track, three times for previous track.
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