If you want open-ear listening that keeps you more aware of your surroundings for library breaks and outdoor activity, choose FJX Bone Conduction Headphones; if you need a neckband with longer stated battery life and on-ear buttons, choose Keenso Neckband Headset. For quiet library use, the FJX design has the clearer advantage of leaving the ear canal open, while the Keenso is the more conventional in-ear option with a flexible band worn around the neck.
• FJX’s biggest strength: open-ear bone-conduction design, Bluetooth 5.3, and 32 GB of built-in MP3 storage. Trade-off: its stated battery life is 4 hours, and Bluetooth is not intended for underwater listening.
• Keenso’s biggest strength: up to 13 hours of talk or music time, with volume and track controls on the headset. Trade-off: it uses in-ear earpieces, so it does not leave your ear canals open.
• For the library: FJX is the more plausible fit if you want to hear some surroundings; neither product’s specs establish how much sound reaches people nearby.
• For workouts and swimming: FJX supports swimming with MP3 mode; Keenso is rated IPX7 for sweat and rain, not described as a swimming headset.
• Choose FJX for open-ear listening, local music playback, and swimming use; choose Keenso for a neckband, calls, and longer stated battery life.
FJX is built around a different idea from ordinary in-ear headphones. Its open-ear design sits behind the ears, with bone-conduction drivers transmitting sound through vibrations rather than sealing the ear canal. That can appeal to someone who wants music or audio while keeping their ears uncovered. For a library visit, that distinction may matter if you prefer not to block out every surrounding sound. It does not, however, make these headphones a substitute for attentive listening to people or announcements.
The design is also aimed at movement and water. FJX lists an IP68 waterproof rating and describes use in rain and swimming. Its Bluetooth 5.3 connection is for compatible devices, but the product information warns that water affects Bluetooth signals. For swimming, the intended alternative is MP3 mode: the headset has 32 GB of built-in storage for music played directly from the device. That means a swimmer can listen without relying on a phone connection in the water. Music needs to be transferred to the headset first.
The battery figure is 4 hours, which is a meaningful limitation for a long day away from charging. The supplied information also gives a 1.5-hour charging time and describes the headset as weighing 29 g, with an ultra-light titanium build. I’d consider FJX for shorter listening sessions, outdoor exercise, or swimming with stored audio, but I would plan around its shorter stated battery life. Its controls include media control, and the listed features describe tapping to switch between Bluetooth and MP3 modes or call a voice assistant.
How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Who should skip it: Skip FJX if your priority is a long listening session on one charge, or if you want conventional in-ear isolation rather than an open-ear fit.
Keenso takes the more familiar neckband approach: the band rests around the neck, and the earpieces sit in the ears. Its listed battery life is up to 13 hours for talk or music, a much longer figure than FJX’s 4 hours. That makes it the more practical choice on paper for someone who wants to listen through a full workday or several workouts without planning a recharge between sessions. The neckband also keeps the controls close at hand rather than requiring every adjustment through a connected phone.
The headset uses Bluetooth 5.1 and is described as compatible with smartphones, tablets, laptops, and TVs that support Bluetooth. Its listed wireless range is about 32.8 feet. On-ear push buttons control functions such as volume, track changes, and calls. A noise-reduction microphone is specified for voice calls, and the product description mentions noise-reducing audio design. Those details may suit someone who expects to alternate between music and calls, though they do not tell us how effectively the headset blocks surrounding noise or how it sounds in a busy room.
Keenso’s IPX7 rating is described for sweat and rain, making it relevant to workouts and outdoor activity in wet weather. The sheet does not describe it as suitable for swimming. It charges through Micro USB, and its battery capacity is listed as 150 mAh. Those details are worth noting if you already have a preferred charging setup or need to coordinate charging around regular use. For a library, its in-ear fit may be appealing if you want earpieces that sit inside the ears, but the available specifications do not establish sound leakage or isolation performance.
Who should skip it: Skip Keenso if you specifically want open-ear bone conduction, built-in MP3 storage, or a headset described for swimming.
• Best for keeping the ear canal open → FJX Bone Conduction Headphones. Its open-ear bone-conduction design does not use the in-ear placement listed for Keenso.
• Best for longer stated battery life → Keenso Neckband Headset. It lists up to 13 hours of talk or music, compared with FJX’s 4-hour battery figure.
• Best for swimming with stored audio → FJX Bone Conduction Headphones. Its IP68 rating and MP3 mode are specifically described for swimming; Bluetooth may not work reliably underwater.
• Best for calls and quick adjustments → Keenso Neckband Headset. It has push-button controls for volume, tracks, and calls, plus a noise-reduction microphone.
• Best for listening without a connected phone → FJX Bone Conduction Headphones. Its 32 GB of storage supports local MP3 playback after audio is transferred to the headset.
• Best for sweat and rain during workouts → Either, with different limits. FJX is rated IP68 and described for swimming; Keenso is rated IPX7 and described for sweat and rain.
• Best for a library listener who wants open ears → FJX Bone Conduction Headphones. Its design leaves the ear canal open, though it is still sensible to keep the volume considerate in a shared space.
• Best for someone who prefers a neckband and in-ear fit → Keenso Neckband Headset. Its flexible neckband and in-ear earpieces suit people who want that familiar arrangement.
Buying Considerations
Think about how long you need to listen between charges. Keenso’s up-to-13-hour figure is the stronger fit for extended use, while FJX’s 4-hour battery life may be enough for a shorter library visit or workout. FJX offsets that shorter battery figure with MP3 storage, which can be useful when you want to leave your phone behind or listen in water where Bluetooth is affected. The storage does not change the stated battery life, so it is still worth considering your session length.
Water resistance is not a single interchangeable feature. FJX is listed as IP68 and described for swimming, with MP3 mode recommended underwater. Keenso is IPX7 and described for sweat and rain. If swimming is central to the decision, those distinctions point toward FJX; if your use is running or gym sessions where sweat and rain are the concern, Keenso’s listed protection may be sufficient. Neither specification alone describes every possible use condition.
Finally, match the wearing style to your preference. Someone searching for “on ear headphones for library” should know that these are not described as traditional on-ear headphones: FJX is open-ear and rests behind the ears, while Keenso is in-ear with a neckband. The two designs also offer different trade-offs in awareness, fit, and controls. I’d decide first whether open ears or an in-ear fit matters more, then weigh battery life and water use.
I would choose FJX Bone Conduction Headphones for a library-focused buyer who wants an open-ear design and may also use the headset outdoors or for swimming with MP3 playback. That combination is more distinctive for my needs than Keenso’s longer battery life. The 4-hour figure is a real constraint, so I would choose Keenso instead if I needed longer listening sessions or wanted in-ear earpieces with buttons for calls and music. For the library, my pick is FJX because its open-ear design better matches the kind of listening I’d want in a shared space.
FAQ
FJX has the open-ear design, so it does not seal the ear canal. Keenso uses in-ear earpieces. The specifications do not establish how much sound either product leaks or how much outside noise it blocks, so keep shared-space volume in mind.
The product information says water affects Bluetooth transmission and advises against Bluetooth mode while swimming. FJX includes 32 GB of storage for MP3 playback, which is the described option for listening in water.
Keenso is listed as IPX7 and described for sweat and rain during activities such as workouts and outdoor exercise. The available information does not describe it as a swimming headset, so FJX is the more directly specified choice for swimming.
Keenso lists up to 13 hours of talk or music time. FJX lists an average battery life of 4 hours and a charge time of 1.5 hours, so Keenso has the longer stated listening time.
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