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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-05 · 7 min read · Independent comparison
• H2O Audio Surge S+ Waterproof — biggest strength: IPX8 waterproofing rated for complete submersion to 12 ft / 3.6 m, plus five sizes of earplugs (XS–XL) and a tree tip set to lock the fit during activity.
• H2O Audio Surge S+ Waterproof — biggest trade-off: it's a wired 3.5 mm design with a short cord aimed at body-worn MP3 players, so it isn't the wireless, cable-free setup most people picture for a desk.
• KZ Zax — biggest strength: a 7BA+1DD hybrid setup with 16 sounding units across both sides, a 10 Hz–40 kHz frequency range and up to 36 dB of sound isolation from a deep in-canal seal.
• KZ Zax — biggest trade-off: it's a wired, over-the-ear-loop monitor with a detachable 2-pin cable and no mic on this version, so it's tethered and not built for water.
• Who each pick is for: H2O Audio Surge S+ Waterproof for swimmers, runners and heavy sweaters who need water and sweat protection above all; KZ Zax for listeners and streamers who want maximum detail and isolation in a wired monitor.
The Surge S+ is a specialist, and it's proud of it. The headline spec is the IPX8 rating: these in-ear headphones are built to handle heavy perspiration, rain and complete submersion down to 12 ft / 3.6 m. If your version of "listening" happens in a pool, on a board, or in a downpour, that single number matters more than anything else on this page. H2O Audio has been building water-sports audio since 2003, and the design shows it — the rounded-tip earpieces sit flush with the ear and are shaped to align the bud with your ear canal, which is exactly the kind of detail that keeps a seal from breaking mid-stroke.
Comfort and fit get real attention here. You get five sets of earplugs spanning XS to XL plus a tree tip set, so you can dial in a secure fit instead of hoping the stock tips happen to match your ears. The sound-isolating, watertight earplugs are what create the warm bass response, and the dynamic drivers cover a 20 Hz–20,000 Hz range at 16 ohm impedance — easy to drive from a basic player. The short-cord design is deliberate: it's made to pair with an armband or a small body-worn MP3 player so the cable isn't flapping around while you move.
Who should buy it? Swimmers first, obviously, but also runners, cyclists, gym-goers, surfers and paddle boarders who destroy ordinary earbuds with sweat. The one-year warranty against defects in materials and workmanship is a nice bit of reassurance for a small-brand purchase. Who should skip it? Anyone who wants wireless freedom, a mic for calls, or a cable long enough to reach a laptop across a desk. For webinars, this is a "if you happen to own it" option at best — the isolation helps you focus, but the short cord and wired 3.5 mm connection make it awkward as a daily desk companion. It's a sport tool, not a conference tool.
The KZ Zax is the opposite kind of specialist: a wired in-ear monitor obsessed with driver count and detail. Sixteen sounding units across both sides, split across low, mid, high and ultra-high bands, sit behind a 10 Hz–40 kHz frequency range, 24 ohm impedance and 113 dB sensitivity. The bass comes from a 10 mm PEK spring diaphragm dynamic driver, while the balanced armature array handles the upper registers. In plain terms, this is a design meant to surface layers in a mix — the kind of earphone people reach for with symphonic recordings, chamber strings or dense vocal productions. A silver-plated oxygen-free copper cable is included, and the 2-pin 0.75 mm connector is detachable, so the cable is replaceable rather than the whole unit.
Fit is the other half of the story. The nozzle pipes sound directly into the ear canal rather than sitting outside it, which is what allows up to 36 dB of noise blocking — a physical seal doing the work, not electronics. The over-the-ear loop keeps the cable anchored so it doesn't get yanked out, and KZ describes a 45-degree angled insertion with the cable routed behind the ear. The zinc alloy faceplate over a transparent cavity is a nice touch: it resists the metal oxidation that dulls cheaper shells over time, and you can see the internals.
So who should buy it? Anyone who wants a wired monitor for focused listening, streaming or long webinar sessions where blocking out a noisy room is the whole point. The ergonomic, lightweight over-ear design is explicitly aimed at fatigue-free wear over long stretches. Who should skip it? Swimmers and heavy sweaters — there's no water-resistance rating here, so sweat and rain are a real risk. And if you need a built-in mic for calls, this particular version doesn't include one, so you'd be handling audio separately.
• Best for water and sweat → H2O Audio Surge S+ Waterproof. IPX8, full submersion to 12 ft / 3.6 m, and watertight earplugs. Nothing about the Zax competes here.
• Best for sound isolation → KZ Zax. Up to 36 dB of blocking from a deep in-canal seal, versus sound isolation on the Surge S+ that isn't rated in decibels.
• Best for detail and frequency range → KZ Zax. 10 Hz–40 kHz with a 16-unit hybrid array against the Surge S+'s 20 Hz–20,000 Hz dynamic drivers.
• Best for secure fit during movement → H2O Audio Surge S+ Waterproof. Five earplug sizes (XS–XL) plus a tree tip set, with a flush, canal-aligned shape.
• Best for long desk or streaming sessions → KZ Zax. Over-ear loop, lightweight build and an ergonomic shape designed to stay comfortable for hours.
• Best for replaceable parts → KZ Zax. The detachable 2-pin 0.75 mm cable means a worn cable doesn't kill the earphones.
• Best for pairing with a body-worn player → H2O Audio Surge S+ Waterproof. The short cord is made for an armband or a small MP3 player, not a laptop.
• Best for wireless convenience → neither. Both are wired 3.5 mm designs, so if you specifically want the best comfortable bluetooth earbuds for webinars or the best foldable true wireless earbuds for webinars, you're shopping in the wrong category here.
For webinars and anything desk-bound, I'd buy the KZ Zax. The 36 dB of isolation and the over-ear, fatigue-free design are exactly what you want when you're sitting through a long call in a noisy house, and the hybrid driver array gives you far more detail to work with. In my opinion it's the sharper tool for focused listening. If your priority is water — swimming, surfing, sweating through a run — I'd take the H2O Audio Surge S+ Waterproof without hesitation, because IPX8 submersion protection is something the Zax simply doesn't offer. Two different jobs, two different answers. Think about which one describes your actual week. Check the current price on Amazon before you commit to either.
FAQ
Start with the smallest tip that still seals, then work up. The H2O Audio Surge S+ Waterproof includes five earplug sizes from XS to XL plus a tree tip set, and its rounded shape is designed to sit flush and align with the canal. The KZ Zax uses a 45-degree insertion angle with the cable looped over the ear and routed behind it.
Most in-ear models don't open — you swap tips rather than disassemble them. The KZ Zax is the exception in one sense: its 2-pin 0.75 mm cable detaches, so you can separate the cable from the shells. The H2O Audio Surge S+ Waterproof is a sealed, waterproof design, so there's nothing to open; you change earplugs and go.
Only if you want a headband instead of in-ear fit. Between these two, the KZ Zax is the better webinar choice thanks to its over-ear cable routing, lightweight build and up to 36 dB of isolation. The H2O Audio Surge S+ Waterproof is the better pick for water and sweat, not for long desk sessions.
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