We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-28 · 7 min read · Independent comparison
If you want a featherweight ear-clip design that stays put through runs and workouts with 18+ hours of playtime, choose Koss KSC35; if you need a foldable on-ear headphone with up to 50 hours of battery life and fast USB-C-style recharging in about two hours, choose Amazon Renewed Beats Solo 4.
• Koss KSC35 biggest strength: A clip-on ear design that grips your ear for active use, plus 18+ hours of battery and a bundled carrying case for portability.
• Koss KSC35 biggest trade-off: No active noise cancellation, a plastic-and-foam build, and a long 6-hour charge time that rewards planning ahead.
• Amazon Renewed Beats Solo 4 biggest strength: A custom acoustic architecture with updated drivers, up to 50 hours of battery, and a recharge that finishes in roughly 135 minutes.
• Amazon Renewed Beats Solo 4 biggest trade-off: It is a renewed unit rather than new, and the controls lean on voice and media buttons instead of a full remote.
• Choose Koss KSC35 if you want a lightweight clip-on for running, workouts and travel.
• Choose Amazon Renewed Beats Solo 4 if you want long battery life and a foldable on-ear headphone with Beats sound.
The Koss KSC35 is built around a genuinely unusual idea: instead of clamping a band over your head, it clips around each ear. That ear-clip design is the whole personality of this headphone. Koss describes it as securing tightly around the ear, and for anyone who has had earbuds fall out mid-jog or a headband press uncomfortably during a workout, that approach makes immediate sense. It is aimed squarely at active listeners — running, training, traveling.
Under the hood, the specs are more serious than the featherweight look suggests. The dynamic drivers cover a 15 Hz to 25 kHz frequency range, which is a wide spread, and Koss frames the tuning around deep bass and a strong midrange. Impedance is listed at 60 ohm. Bluetooth 5.2 handles the wireless connection with a stated range of about 10 meters, so you can leave your phone on a bench or in a bag and keep listening. There is an integrated microphone and an audio remote, so you can take calls, adjust volume, and pause or skip tracks without touching your phone. Voice assistant activation is supported too.
Who should buy it? In my opinion, the KSC35 is the better pick for a runner, cyclist, or gym-goer who wants nothing sitting inside their ear canal and nothing pressing on top of their head. Who should skip it? If you want isolation from airplane noise or a busy office, this is not that product — noise control is listed as none, and the open clip-on fit naturally lets the world in.
Amazon Renewed Beats Solo 4: Who It's For
The Beats Solo 4 is a different animal entirely. This is an on-ear headphone with a headband, a folding frame, and a matte black finish built from metal and plastic. Beats leans on a custom acoustic architecture with updated drivers, which is the company's way of saying the sound engine was reworked rather than carried over. It is Bluetooth 5.3, the newer wireless standard of the two here, and it works with both Apple and Android devices — a real convenience if you switch between a phone and a laptop.
The headline number is battery: up to 50 hours of average life, with a charge time of about 135 minutes. That combination is the opposite of the Koss approach. You get far more listening per charge and you get it back far faster. For a commuter, a student, or anyone who treats headphones as an all-day accessory, that math is compelling. The Solo 4 also folds, which makes it easier to toss into a backpack than a rigid on-ear headphone.
The trade-offs are worth being straight about. First, this listing is Amazon Renewed, which Amazon describes as products that work and look like new and are backed by the Amazon Renewed Guarantee, with a one-year manufacturer warranty noted here. Renewed is a legitimate way to buy, but it is not the same as factory-new, and buyers who want a sealed box should know that going in. Second, controls are voice-based with media control buttons rather than a full inline remote, and noise control is listed as none — so no active noise cancellation here either. Third, the ear placement field on this listing is inconsistent (it reads "In Ear" in the product data while the product name and design clearly describe an on-ear headphone), so treat the on-ear description as the accurate one.
Who should buy it? In my opinion, the Solo 4 suits someone who wants maximum battery, fast recharging, a foldable on-ear fit, and the Beats sound signature — and who is comfortable buying renewed to get there. Who should skip it? Anyone who needs a secure clip-on for high-impact training, or who insists on a brand-new unit.
Side-by-Side: Which Should You Choose?
• Best for running and workouts → Koss KSC35. The ear-clip design is made to stay on during movement.
• Best for fast recharging → Amazon Renewed Beats Solo 4. About 135 minutes versus roughly 6 hours.
• Best for lightweight, barely-there wear → Koss KSC35. It weighs 3.8 ounces and skips the headband entirely.
• Best for portability with protection → Koss KSC35. A carrying case and cable clips are included.
• Best for newer wireless standard → Amazon Renewed Beats Solo 4. Bluetooth 5.3 versus Bluetooth 5.2.
• Best for call and volume controls on the cord-free remote → Koss KSC35. It has an integrated microphone with an audio remote.
• Best for buyers who want a new, sealed product → neither, strictly speaking. The Beats listing is renewed; the Koss is the new-unit option here.
If I had to pick one, I would buy the Koss KSC35. Not because it wins every category — it does not — but because it is a new product with a clear, specific purpose: a clip-on headphone for people who move. The 15 Hz–25 kHz range, the 18+ hours of playback, the included case, and the on-board mic and remote cover the essentials for training and travel. The 6-hour charge time is the real annoyance, and the lack of noise cancellation is a genuine limitation.
I would choose the Amazon Renewed Beats Solo 4 instead if battery life and recharge speed are your top priorities, or if you simply prefer an on-ear headband fit and Beats tuning. The 50-hour battery and 135-minute recharge are genuinely better numbers, and Bluetooth 5.3 is the newer standard — just go in knowing it is a renewed unit. Before either purchase, check the current price on Amazon, since that is the one variable I cannot weigh for you here.
FAQ
how to clean on ear headphones
Wipe the ear pads and headband with a soft, slightly damp cloth, then dry them fully before use. For the Koss KSC35, the foam cushions can be swapped for Koss replacement cushions, which is the simplest way to refresh a worn pad. Avoid soaking any headphone, since neither model here is described as water-resistant.
how to fit on ear headphones
how to open ear headphones
If you mean opening the headband to put them on, grip both earcups and gently pull them apart just enough to clear your head, then let the band settle. The Beats Solo 4 folds for storage, so unfold it fully before placing it on. Do not force the frame past its natural range, as the metal and plastic hinges are not designed to over-extend.
how to ear headphones
If you are asking how to wear them, the answer depends on the design: the Koss KSC35 clips around each ear with the driver facing your ear canal, while the Beats Solo 4 sits on top of your ears with the headband over your head. Match the left and right markings, then adjust for a snug but comfortable seal. Neither model has active noise cancellation, so fit is your main tool for blocking out background sound.
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