CSX vs PRO vs FITS. Which Fit is Right for You

CSX vs PRO vs FITS | Which Fit is Right for You?
Interested in Ultimate Ears but not sure which model is right for you? Learn about the differences between our CSX, PRO and FITS lines to find the perfect pair.


Between our new UE FITS earbuds, custom CSX earphones, and legendary PRO in-ear monitors, it can be difficult to choose just one. While it makes sense for some people to have multiple pairs for different uses, many of us only need a single pair to start out. 


In this blog, we’ll break down the differences between our CSX, PRO and FITS lineups to help you choose the right model for you.



Custom Fit vs Instant Fit


The biggest difference between our CSX, PRO and FITS models is the fit. CSX and PRO earphones are custom fit to your unique ear shape for unparalleled comfort and noise isolation. Whether you use our custom Fitkit to capture a comfortable mold of your ears from home or visit a trained audiologist for a professional fitting, you can rest assured that your in-ear monitors or earphones will fit like a glove. Our team handcrafts each pair of PRO and CSX earphones based on your ear molds, a process that takes several hours and 100+ individual touch points.


FITS ear tips are made of a soft photopolymer gel and use patented Lightform Technology to instantly adjust to the shape of your ears for a quick, convenient and comfortable fit. Once you put the soft gel tips into your ear and adjust for comfort, the UE FITS app activates tiny LED lights inside the earbuds which harden the gel in 60 seconds. The result? Earbuds that are instantly custom-fitted for your ears only. 


Ultimate Ears CSX


UE CSX: Ultimate Sound and Comfort


Handcrafted for exceptional comfort and a precise fit, UE CSX earphones deliver premium sound quality and 26 dB of noise isolation for a powerful listening experience that brings out the energy and emotion of the music you love. Each pair of UE CSX earphones are precision-tuned by hand and custom tailored for your ears—right down to the electronics and audio components.


It starts with our universal Fitkit, which uses cutting-edge technology to make an impression of your ears in minutes, right from the comfort of your own home. After you order your earphones, you’ll receive a UE Fitkit via mail. Follow the simple instructions on our UE Fitkit smartphone app to create a highly accurate impression of your ears. Then, mail back the Fitkit with the included prepaid shipping label and we’ll build your bespoke earphones from scratch.


Our universal Fitkit provides a tighter seal than Lightform technology (used for UE FITS), but not quite as deep as a mold from an audiologist (used for UE PRO). That’s why CSX earphones provide an ideal experience for everyday listening.


Not only are UE CSX earphones customized to the shape of your ears, you can also match the design to your unique personality and style. Choose from a wide range of custom faceplate colors and premium materials like wood and mother of pearl. You can even upload your own custom artwork or switch up your style any time you want with UE SWITCH interchangeable faceplates. 


It’s not all about looks though—UE CSX earphones sound great too. You’ll hear details in your favorite songs that you’ve never noticed before thanks to our top-of-the-line balanced armature drivers and the immersive experience of passive noise isolation achieved with the custom fit of CSX. Plus, the UE Custom app’s powerful equalizer gives you complete control over the sound of your music, so every song feels like it’s been custom mixed just for you. Choose from five models, each with their own unique sound signature:


  • UE 5 CSX: Balanced Sound For All-purpose Listening

  • UE 7 CSX: Extra Midrange Detail For Vocals And Acoustic Instruments

  • UE 11 CSX: Extended Low-end Response For Bass-heavy Music

  • UE 18+ CSX: Ultra-pure Audiophile Sound With Extra Headroom

  • UE LIVE CSX: The Best Of The Best—Clarity, Detail And Plenty Of Bass



Music lovers, audiophiles, travelers and anyone looking for a premium acoustic experience anytime, anywhere.
IPX Bluetooth cable with mic and swappable IPX auxiliary mic cable.
Reaches the first bend of the ear canal for all day comfort.
At-home Fitkit



Ultimate Ears PRO

UE PRO: Unparalleled Performance For the Stage, Studio and Beyond


Whether you’re performing on stage, recording in the studio or live streaming on the web, Ultimate Ears PRO in-ear monitors provide exceptionally detailed, full-range sound with neutral frequency response and a secure custom fit that will withstand any performance.


UE PRO in-ear monitors are professionally fitted to each ear by trained audiologists using highly detailed impressions that reach the second bend of the ear canal, providing superior sound and isolation. Each pair of UE PRO in-ear monitors provides 26 dB of gain reduction, protecting your hearing in noisy environments.


The more detailed fit of UE PRO also prevents an annoying issue common in commercial earbuds. When you move your jaw—such as while you’re singing—the shape of your inner ear changes. Most commercial earbuds are unable to compensate for this, causing the sound to change as you sing. This is known as “occlusion.” At best it’s annoying and at worst it can be disorienting enough to throw off your entire performance. Because UE PRO IEMs go to the second bend of your ear canal, they reduce the occlusion effect, retaining the same sound even when you’re reaching for that high note.


UE PRO in-ear monitors are available in seven different models, each with their own unique sonic signature. All of our UE PRO in-ear monitors utilize top-quality balanced armature drivers to deliver clear, detailed sound across the entire frequency spectrum. Each driver is fine-tuned to a different frequency range to create a neutral, balanced frequency response, unlike the common dynamic drivers found in most popular headphones and earphones.


Designed for professionals, UE PRO in-ear monitors are crafted to meet the needs of the most demanding shows and sessions. With a small, lightweight form factor that’s easy to take anywhere, UE PRO is ready to go on the road, into the studio or wherever inspiration strikes. The award-winning IPX Connection System and SuperBAX cable are custom-built to withstand daily use, minimizing the need for service and maintenance. This durable, waterproof connection system is designed to last a lifetime.


If you’re ready to take your performance to the next level, check out our lineup of UE PRO in-ear monitors, custom-tuned to deliver professional sound quality for performing, creating and more:




Musicians, performers, speakers, sound engineers and technicians in the music industry.
Ultimate Ears IPX SuperBax Professional Stage Cable.
Reaches the second bend of the ear canal for the most secure fit possible.
Audiologist impressions or 3D ear scan by a UE technician.

You may be wondering, “What’s the difference between UE PRO and UE CSX?” Both offer the same sound quality, utilize the same incredible technology and are handcrafted by the same team. The only difference is the depth of the fit and how you get your impressions done. 


UE PRO in-ear monitors fit deeper into your ear canal for the most secure fit possible — even if you’re doing backflips on stage. UE PRO requires a trip to the audiologist. 


UE CSX earphones offer a fit that’s more appropriate for everyday listening and don’t require a visit to an audiologist. Since they only reach the first bend of your ear canal, they're easier to take in and out of your ears without sacrificing a snug and secure fit.


Ultimate Ears FITS


UE FITS: Custom Fit to Your Ears In 60 Seconds


The newest addition to the Ultimate Ears family, UE FITS are the world’s first true wireless custom-fitted earbuds. Unlike traditional earbuds, which become uncomfortable after a couple of hours or less because they apply more pressure to certain parts of the ear than others, FITS are custom-molded to your unique ear shape so you can wear them all day in total comfort. Plus, the secure fit will stay in place no matter what activity you’re doing.


UE FITS uses cutting-edge Lightform technology to mold to your ears in just 60 seconds. FITS ear tips are made of a soft gel called a photopolymer—a plastic that reacts to light. Once you put the soft gel tips into your ear and adjust for comfort and a good seal, the UE FITS smartphone app activates tiny LED lights inside the earbuds which harden the gel ear tips.


It may seem like magical technology from the future, but UE FITS create the perfect fit in less time than it takes to make a cup of coffee. We’re so confident in our technology that each pair of FITS is backed by the Perfect Fit Guarantee. The UE FITS app features a fit test that will help you determine if your fit is perfect. And if it’s not, we’ll send you a new pair of moldable tips free of charge. Plus, our team is available to walk you through the process if you need any additional help. 


But UE FITS aren’t just the most comfortable earbuds you’ve ever worn, they’re also some of the best-sounding. Equipped with premium 10mm dynamic audio drivers that have been fine-tuned to faithfully reproduce music as it was meant to be heard, FITS deliver full, warm and detailed sound, with deep and punchy bass. If you’re looking for a specific sound, you can also adjust the tone of your FITS via the EQ tuner in the UE FITS app.


UE FITS is also a stellar choice for music fans who want to block ambient noise without sacrificing audio quality. Thanks to their secure fit and seal, FITS block out distracting noise so you can hear every note or phone conversation at safer volumes. Unlike the active noise cancellation (ANC) found in other earbuds that use sound-degrading frequencies to neutralize outside noise, UE FITS uses advanced tech to keep the audio pure so you can enjoy the highest-quality sound. 


Music lovers, athletes, and anyone looking for True Wireless earbuds with professional audio quality.
USB-C charging case.
Reaches the first bend of the ear canal for all day comfort.
Lightform technology forms a perfect fit in 60 seconds for instantly customized earbuds.


Still can’t decide? Just send us an email, give us a call, or use our website's live chat. Our team will be happy to help you find the right model for you!



Ultimate Ears FITS vs. CSX vs. PRO

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