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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-24 · 7 min read · Independent comparison
• OSSZIT 30 biggest strength: You get 30 individually sealed pairs in one box, each with an adjustable headband, a 3.5 mm plug and a 4 ft cord — a ready-made class set.
• OSSZIT 30 biggest trade-off: No microphone, no volume limiting, and it's a wired 3.5 mm only design, so it won't plug into USB-C-only devices without an adapter.
• KONNAO Upgrade USB Type biggest strength: Kid-specific design with a USB-C connector, an inline volume control, passive noise cancellation and selectable 85 dB / 94 dB volume limiting.
• KONNAO Upgrade USB Type biggest trade-off: It's a single pair with a USB-C connector, so it's the wrong shape of purchase for a whole class and it won't fit older 3.5 mm-only gear.
• Who OSSZIT 30 is for: Teachers, librarians, test coordinators and anyone buying headphones in volume for shared use.
• Who KONNAO Upgrade USB Type is for: A parent buying one pair for one child who uses a USB-C tablet, Chromebook or phone.
The OSSZIT 30 is a bulk purchase first and a headphone second. You get 30 sets of black headphones, each one individually sealed, which matters more than it sounds: individually wrapped pairs are easy to hand out, easy to store, and easy to keep track of when devices get swapped between students. The headband is adjustable and the build is deliberately light, which is exactly what you want when the same pair gets worn by a 7-year-old in first period and a teenager in fourth.
On the audio side, the specs are modest but sensible. Dynamic drivers, a 20 Hz to 20,000 Hz frequency range and 32 ohm impedance mean these will run happily off a phone, tablet, Chromebook or laptop headphone jack without needing an amp. The 3.5 mm plug and 4 ft cord are the classic classroom combination — long enough to reach a desk-mounted device, short enough not to become a trip hazard. It's a wired, non-wireless design, so there's nothing to pair, nothing to charge, and nothing to lose.
Buy it if you're outfitting a classroom, library, museum, hotel or gym and need many pairs at once, or you're running standardized testing where mismatched personal headphones cause problems. Skip it if you need a microphone for calls or online classes, volume limiting for a young child, or USB-C connectivity — none of those are here.
KONNAO Upgrade USB Type: Who It's For
The KONNAO Upgrade USB Type is the opposite philosophy: one pair, built around one kid. The headline feature is the adjustable volume limit with two settings, 85 dB and 94 dB. That's a genuinely useful design choice for parents, because 85 dB is the more protective setting for younger children and 94 dB gives more headroom for older kids in noisier environments. Being able to switch between them means the same pair can grow with a child instead of being replaced.
Connectivity is the other defining trait. This is a USB-C headset, not a 3.5 mm one, so it's aimed squarely at modern tablets, laptops and phones that have dropped the headphone jack. There's a built-in microphone, which the OSSZIT simply doesn't have, and that turns this from a listening device into something usable for video lessons, voice chat and recorded reading practice. The inline remote carries the volume control.
Comfort and isolation are handled differently too. It's an over-ear design in plastic — over-ear cups typically sit around the ear rather than pressing on it, which tends to suit longer sessions better than on-ear. It also lists passive noise cancellation, which is the physical kind: the cups block some outside sound rather than any electronics doing the work. Impedance is 20 ohm, drivers are dynamic, and the range is the same 20 Hz to 20,000 Hz you'd expect at this level. Item weight is 0.22 kg, so it's light enough for a child to wear without complaint. KONNAO covers it with a 2-year warranty, and it ships with a user manual — a small thing, but it helps when you're figuring out the volume-limit switch.
Buy it if you're buying for one child, your devices are USB-C, and you want a mic plus a volume ceiling. Skip it if you need multiple pairs, your gear only has a 3.5 mm jack, or you want a cable that works with any older device in the house.
Side-by-Side: Which Should You Choose?
• Buying for a whole class or a lab → OSSZIT 30. Thirty sealed pairs with adjustable headbands is a package deal; the KONNAO is a single unit.
• Need a microphone → KONNAO Upgrade USB Type. OSSZIT 30 has no mic at all.
• Need volume limiting for a young kid → KONNAO Upgrade USB Type. The 85 dB / 94 dB switch is the single most kid-specific spec in this comparison.
• Devices with a 3.5 mm jack → OSSZIT 30. A standard 3.5 mm plug plus a 4 ft cord is the most universally compatible combination here.
• USB-C-only devices → KONNAO Upgrade USB Type. The USB-C connector is native, not adapted.
• Shared, wipe-down use → OSSZIT 30. Wipe-clean ear cushions and individual sealing are built for turnover.
• Longer wear sessions → KONNAO Upgrade USB Type. Over-ear cups and passive noise cancellation generally suit extended listening better than on-ear.
• Maximum device flexibility → OSSZIT 30. Wired 3.5 mm works with phones, Chromebooks, tablets, laptops and audio equipment; USB-C does not.
In my opinion, most people searching these two names are actually asking two different questions, and that's why I won't pretend there's one winner. If your job is getting headphones onto many heads — a classroom, a testing room, a library — I'd buy the OSSZIT 30, because 30 sealed adjustable pairs with wipe-clean cushions solves a logistics problem that a single premium pair can't. If you're a parent buying for one child on a USB-C device, I'd buy the KONNAO Upgrade USB Type instead: the volume limit, the mic and the 2-year warranty are worth more to you than a bulk count you'll never use. Match the purchase to the headcount and the port, and you'll be happy either way.
how to adjust headphones on iphone
With the OSSZIT 30, slide the adjustable headband to fit and plug the 3.5 mm jack into the phone — on iPhones without a headphone jack you'd need an adapter. The KONNAO Upgrade USB Type connects via USB-C, so it suits USB-C devices rather than Lightning ones. Physical fit comes from the adjustable headband on both.
how to adjust headphones
On both of these, the adjustable headband is what you slide to change fit. Volume is handled differently: the OSSZIT 30 uses an inline remote on the cable, while the KONNAO Upgrade USB Type has an inline volume control plus a switchable 85 dB / 94 dB volume limit. Neither has on-cup controls.
how to adjust headphones volume
Use the inline remote on the cable. On the KONNAO Upgrade USB Type you also set the ceiling itself — choose 85 dB or 94 dB — which caps how loud the headphones can get, a feature the OSSZIT 30 does not have. On the OSSZIT 30, volume is entirely up to the connected device.
how to adjust headphones sound
Neither model has an app, EQ or sound modes, so "adjusting sound" here means adjusting the source: your phone, tablet or laptop's own settings. The KONNAO Upgrade USB Type adds passive noise cancellation, which reduces surrounding noise physically rather than changing the audio profile. The OSSZIT 30 is a straight stereo 3.5 mm pair with no tone controls.
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