How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-30 · 7 min read · Independent comparison
• Monster Open Ear AC520 — biggest strength: Bluetooth 6.0 with a 33-foot range, up to 24 hours of total playtime with the charging case, and an IPX6 rating that shrugs off sweat and rain.
• Monster Open Ear AC520 — biggest trade-off: Earbuds only, not a single sealed unit, so it is not built for swimming; no swim mode, no built-in memory.
• Sanag Swimming Bone Conduction — biggest strength: IPX8 waterproofing with submersion up to 2 meters, a one-piece seamless body, plus 32GB of built-in MP3 memory so you can swim without a phone.
• Sanag Swimming Bone Conduction — biggest trade-off: Only up to 8 hours of playtime per charge, and you must switch to MP3 mode in the water because Bluetooth cannot transmit underwater.
• Pick the Monster if your day is land-based: office, gym, rainy commute, hands-free calls.
• Pick the Sanag if you train in a pool or open water and want music that follows you under.
The Monster Open Ear AC520 is built around open-ear freedom. The hook-shaped earpieces rest outside your ear canal instead of plugging it, so you keep hearing traffic, announcements and coworkers while your music plays. For anyone who has ever pulled an earbud out to talk to a cashier, that awareness is the whole point. Monster pairs it with "Surround Awareness & Safety" positioning, which is really just a plain description of how open-ear design works — and it is genuinely useful outdoors.
Then there is the design story. The slide-open charging case is styled like a small handbag, and a removable lanyard lets you carry it your way. It is a deliberate style choice, and the white finish keeps it looking clean rather than sporty. If you care about how your gear looks on a desk or clipped to a bag, this is the more distinctive of the two.
Battery life is where it pulls ahead for daily use. You get up to 8 hours on a single charge and up to 24 hours total with the case, with a roughly 2-hour recharge. Bluetooth 6.0 is the newest version here, with a 33-foot range and low-latency sync that keeps audio matched to video. ENC handles call clarity, and AI noise cancellation is aimed at cutting background chatter on calls.
What it does not do: swim. IPX6 covers sweat, splashes and rain, not submersion. There is also no built-in memory and no MP3 mode — every listen needs a paired device. If you want pool laps, this is not the one.
Who should buy it: commuters, gym-goers, office workers, and anyone who takes a lot of calls while wanting to stay aware of their surroundings. Who should skip it: swimmers and anyone who wants music without carrying a phone.
The Sanag Swimming Bone Conduction is a specialist, and it is honest about it. The headline feature is IPX8 waterproofing with submersion rated to 2 meters, plus a one-piece seamless build. That is a different class of water protection than the Monster's IPX6. Pool training, ocean swimming, heavy sweat — this is the one designed to keep going.
Bone conduction is the second half of the story. Instead of firing sound into your ear canal, it vibrates through the bone in front of your ear. You hear your audio and the world around you at the same time, which matters when you are running near traffic or cycling. Sanag uses a magnetic drive oscillator and a fully enclosed sound cavity, which the brand says helps hold sound detail even underwater and limits leakage. The 32-ohm impedance, 20 Hz frequency response and 96 dB sensitivity suggest an easy-to-drive, standard bone-conduction tuning — not audiophile detail, but clear enough for sport.
The smartest part is the 32GB of built-in memory. You load songs onto the headphones and switch to MP3 mode — which you must do when swimming, because Bluetooth signals cannot travel through water. That single design decision is what makes this a real swim product instead of a waterproof pair of earbuds. Pairing takes about 3 seconds, and the stated range is up to 50 feet.
The trade-offs are real. Playtime is up to 8 hours per charge with a 2-hour recharge — no charging case to top it up. The listing shows Bluetooth 5.3 in the spec table while the feature copy says Bluetooth 6.0, so treat the wireless version as "modern, not guaranteed newest." The spec sheet also lists a 3.5 mm jack in the connectivity field, which conflicts with the wireless-only description; I would not count on a wired option. And bone conduction always trades bass depth for awareness — expect that going in.
Who should buy it: swimmers, triathletes, open-water and pool trainers, and runners who refuse to be deaf to traffic. Who should skip it: anyone who wants a charging case, long total battery life, or deep bass for casual listening.
Side-by-Side: Which Should You Choose?
• Best for total battery life → Monster Open Ear AC520. Up to 24 hours with the case versus 8 hours on the Sanag.
• Best for phone-free listening → Sanag Swimming Bone Conduction. 32GB of built-in memory and a switchable MP3 mode.
• Best for calls and everyday noise → Monster Open Ear AC520. ENC plus AI noise cancellation aimed at call clarity.
• Best for style and portability → Monster Open Ear AC520. Handbag-style sliding case, removable lanyard, white finish.
• Best for staying aware outdoors → a tie, for different reasons. The Monster does it with open-ear hooks; the Sanag does it with bone conduction.
• Best for rain and gym sweat → Monster Open Ear AC520. IPX6 is plenty for splashes, spills and sweat.
• Best for pool or ocean sessions → Sanag Swimming Bone Conduction. No contest — this is the only one of the two rated for submersion.
If you are unsure which matters more, ask one question: does water ever go over your ears on purpose? If yes, the Sanag. If no, the Monster.
For most people reading this, I would buy the Monster Open Ear AC520. In my opinion it is the better everyday pair: up to 24 hours with the case, the newest Bluetooth version in this comparison, ENC call handling, and an open-ear fit that works from the office to the gym to a rainy walk home. The handbag-style case is a nice bonus if you like gear that looks intentional.
I would only switch to the Sanag Swimming Bone Conduction if swimming is the actual job. Its IPX8 rating, 2-meter submersion tolerance and 32GB of built-in memory make it a purpose-built tool that the Monster simply is not. Buy the Monster for your day. Buy the Sanag for your laps. Check the current price on Amazon for whichever one matches your routine.
how to bluetooth headphones to ps5
The PS5 does not accept Bluetooth audio directly, so you need a USB Bluetooth transmitter plugged into the console, then pair the headphones to that transmitter. The Monster Open Ear AC520 uses Bluetooth 6.0 with a 33-foot range and low-latency sync, which suits this setup. The Sanag also supports Bluetooth pairing, but remember its MP3 mode is the one you use in water.
how to bluetooth headphones to xbox
Xbox consoles also block direct Bluetooth audio, so a transmitter plugged into the controller or console is the usual route. Either headphone here can pair to that transmitter once it is in pairing mode. If you plan to use them for gaming and calls in the same day, the Monster's low-latency Bluetooth 6.0 and ENC are the friendlier fit.
how to bluetooth headphones to roku tv
Most Roku TVs do not offer Bluetooth audio output, and Roku's own app-based private listening works with Roku's mobile app rather than third-party headphones. A Bluetooth transmitter on the TV's audio output is the practical workaround for either model. The Sanag's stated range of up to 50 feet gives you more room to move; the Monster is rated at 33 feet.
how to bluetooth headphones
Put the headphones into pairing mode — typically by holding the touch control until the indicator flashes — then open your phone's Bluetooth settings, select the device and confirm. The Monster Open Ear AC520 uses touch and voice control; the Sanag uses on-ear touch controls. The Sanag also pairs in about 3 seconds and can switch to its 32GB MP3 mode when you do not want a phone involved.
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