Keychron K3 HE Review — The First Low-Profile TMR Keyboard?
Low-profile magnetic keyboards are still incredibly rare. Until now, NuPhy was practically alone in this niche with its Air HE series. The Keychron K3 HE makes the category even more unusual: to the best of my knowledge, it is the first low-profile magnetic keyboard built around TMR sensing, and one of the very few to offer full tri-mode connectivity.
It combines a slim 75% design with adjustable actuation, Rapid Trigger, analog input, wired USB-C, 2.4 GHz wireless, and Bluetooth. On paper, it is a rare mix of gaming-focused technology and everyday wireless versatility.
Let's dive into it.
Specs and Features
- Layout: compact 75%
- Dimensions: size — 318.62 x 126 mm, front height 25.4 mm (incl. keycap), back height 22.0 mm (incl. keycaps)
- Typing angles: 2°, 4.5° or 7.5°
- Main body: aluminum frame with natural wood accents
- Bottom case: ABS plastic
- Plate: CNC aluminum
- Stabilizers: plate-mounted
- Switches: Pre-lubed Keychron Ultra-Fast Lime Low-Profile Magnetic switches
- Switch material: POM
- Switch height: 12.1 mm
- Keycaps: LSA-profile low-profile double-shot PBT, shine-through legends, no backlighting
- North-facing RGB
- LED Battery: 2,600 mAh, rechargeable lithium-polymer battery
- Claimed battery life: up to 55 hours
- Connectivity: USB-C wired, 2.4 GHz wireless, and Bluetooth 5.2, Bluetooth pairing up to three devices
- Polling rate: 1,000 Hz wired and 2.4 GHz; 125 Hz Bluetooth
- NKRO: Yes, wired and wireless
- Operating systems: Windows, macOS, and Linux
- Firmware and software: QMK firmware with Keychron Launcher web configurator
- MCU memory: 256 KB
- Hot-swap support: yes, but only for Keychron Ultra-Fast Lime Low-Profile Magnetic switches
- Color options: Black with dark wood accents or white with light wood accents
Magnetic-switch gaming features
- Adjustable actuation: each key can be configured between 0.2 and 2.9 mm, with adjustment increments of 0.1 mm
- Dynamic Rapid Trigger: keys activate and reset according to movement rather than a fixed reset point
- Dynamic Keystrokes: up to four commands can be assigned to a single key, depending on press depth
- Two-stage release actions: additional actions can be triggered while releasing a key
- Last Key Priority (SOCD): prioritizes the most recently pressed directional key
- Snap Click (Rappy Snappy): gives priority to the deeper press when two keys are held simultaneously
- Analog Mode: translates key travel into variable controller-like input for racing games and other analog applications
- Per-key remapping: available through the browser-based Keychron Launcher
- Macros and shortcuts: configurable through Keychron Launcher
- RGB customization: more than 22 lighting effects, static white, per-key RGB, and dual-zone Mix RGB
In the box
- Keychron K3 HE low-profile magnetic keyboard
- Manual
- Quick Start Guide
- Space keycaps (Mac/Win)
- USB-C to C braided cable (L-shaped)
- USB-A adapter
- 8k dongle + adapter
- Keychron stickers
- screwdriver
- keycap/switch puller (cheap)
Unboxing
Sound Test
The Ultra-Fast Lime switches don’t feel as light as their name implies, but they do pop back up fast enough with plenty of control. The additional resistance is nice because it cuts down on inadvertent key presses, without making the board feel lethargic. They are quite comfortable to type on once you get used to them being a low profile switch. The keystrokes feel solid and stable, while the well-spaced keys help prevent mis-strokes.
Soundwise was another pleasant surprise. This keyboard isn’t loud at all. It has a softer and more muted sound profile rather than thin or piercingly loud like a lot of gaming keyboards. It suits both gaming and daily use perfectly.
TMR Technology — what is it?
Tunneling Magnetoresistance, or TMR for short, has been the standard for gaming controllers for many years now. It’s recently started appearing in gaming keyboards, too. TMR works very similarly to Hall Effect sensing: both technologies measure the change in a magnetic field to calculate how far the key is pressed. Fundamentally, they just do it in different ways to achieve the same outcome.
On paper, TMR offers theoretical benefits of higher sensitivity, marginally increased precision, and much lower power consumption. That last piece is important when it comes to something like the Keychron K3 HE. Low-profile keyboards lend themselves well to portable use, and the K3 HE is a tri-mode board with wired USB-C, 2.4 GHz wireless, and Bluetooth connections. A sensor technology that sips power instead of guzzling it makes a lot more sense in this situation than it would for a keyboard that only connects to your desktop via cable.
That being said, you shouldn’t think of TMR as some kind of magical improvement over Hall Effect sensing. The practical benefits of TMR are still up for debate. Modern HE keyboards are more than capable of matching TMR’s professed accuracy and stability. Firmware optimizations, signal processing, and PCB design are arguably just as important (if not more) than the type of sensor you’re using. TMR also doesn’t inherently decrease latency. Your TMR keyboard will not automatically be faster than your HE keyboard just because it uses “newer” sensor technology.
Plus, higher precision isn’t always an inherently good thing in magnetic keyboards. Overly sensitive settings have the potential to create unwanted inputs or make your board feel less stable if not implemented correctly. Sensitivity is great, but only when it can be controlled.
The coolest potential application of TMR might actually be down the line with true Mag-Mech keyboards. Because TMR sensors can read from magnets more effectively at various angles, the PCB can be designed to support both magnetic and regular mechanical switches. Alas, the Keychron K3 HE is not fully Mag-Mech compatible. Magnetic it may be, but it only works with its line of low-profile magnetic switches.
For now, TMR is best used in situations where power efficiency and portability are a real concern. That applies to the K3 HE. It’s one of the few low-profile magnetic keyboards out there. It’s also one of the few wireless magnetic keyboards out there. Even more rare? A TMR tri-mode magnetic, low-profile keyboard.
Design and Build Quality
Speaking of design, the Keychron K3 HE sports a relatively compact 75% layout. As you can see above, the function row sits very close to the number keys, and the navigation cluster is slimmed down to its bare essentials, right next to the Enter key. The compactness saves a ton of desk real estate, but it comes at the cost of accommodating everyone’s workflow. If you come from a more traditional TKL layout, using the K3 HE will definitely take some getting used to due to the placement of certain keys.
Over on the left side of the keyboard, we have the USB-C port, as well as the Mac/Windows switch and tri-mode connectivity switch. On the bottom, you will find rubber feet along with two-stage adjustable feet for users who prefer a steeper angle when typing. The K3 HE is really flat out of the box, which I prefer, but I’m glad that these adjustment options are available if you want them. I also noticed that the feet hold pretty well and can take some abuse. I was able to shove the keyboard across my desk without them folding up accidentally.
Keychron made the shell out of ABS plastic, but dressed it up with aluminum frames along the top and bottom and wooden details along the sides. This wooden finish is easily my favorite design aspect of the keyboard. It makes the K3 HE feel warm and inviting without being overbearing or feeling gimmicky.
Build quality is also really good. The keyboard feels solid, nicely put together, and has a nice heft to it that feels more premium than its thin profile would lead you to believe. Now, don’t get me wrong, if you put the K3 HE next to something like the IQUNIX Magi65 Pro, you will be able to immediately notice that Keychron’s offering sits just a notch below in terms of materials used and overall build refinement. I mention the Magi65 Pro specifically since that is the closest thing I have to directly compare to the K3 HE, but they are obviously in different categories with one being a mechanical keyboard and the other being a low-profile magnetic TMR keyboard. With that said, the Magi65 Pro simply feels more solid in your hands.
Again, there is nothing here that will scream “LOOK AT ME I’M A GAMING PERIPHERAL!” The K3 HE is subtle. It has no exaggerated angles, no unnecessary design choices, and Keychron did a great job at making a minimalistic, clean, and beautiful keyboard.
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Keychron tosses in a set of spare keycaps in the box so you can configure your layout to be either Windows or macOS-oriented.
Keycaps and Switches
The K3 HE sports Keychron’s Ultra-Fast Lime Low-Profile Magnetic switches. They’re pre-lubed POM switches with an advertised total travel distance of around 2.9 mm. They share most of the same quirks as the rest of the keyboard in that they’re custom-built for the slim form factor.
Its name would imply an extremely light and aggressive esports switch, but that is not quite the experience you’ll get. The Ultra-Fast Lime switches actually have slightly more resistance than some other magnetic switches I’ve tried. I do not mind that at all. In fact, I quite enjoy it. They still react quickly and rebound excellently, but the slightly firmer feel prevents stray presses and works better for everyday use.
Speaking of sound, the switches are also quite quiet. Low-profile boards can sometimes sound a bit thin, plasticy, or even slightly hollow. The K3 HE mostly avoids these pitfalls. The profile sounds soft and controlled, with muted acoustics that blow away the loud clacking I was expecting from such a compact gaming keyboard. It’s far from silent, mind you. But it is quiet enough that I can imagine it being fine for office use or shared living spaces.
Although Keychron lists the K3 HE as hot-swappable, that term comes with some caveats. There is no option to use regular mechanical switches, nor can you really experiment with different magnetic switch options. Keychron Ultra-Fast Lime Low-Profile Magnetic switches only. Despite using TMR sensing, it is not actually a full Mag-Mech implementation.
The keyboard ships with LSA-profile double-shot PBT keycaps. They feature a slightly textured surface that is pleasant to the touch and gives your fingers just a bit more grip than a fully smooth surface would. The legends are tasteful and subdued, though they do not shine through. As such, the RGB lighting is mostly just decorative if you intend to use the keyboard in a dark room.
The keycap profile is also worth noting. These are low-profile, slightly sloped keycaps without the exaggerated sculpting you’ll find on many full-size mechanical keyboards. It complements the near-zero-profile of the board itself nicely, but can feel a little odd if you’re more used to Cherry- or OEM-style keycaps.
Granted, PBT keycaps should theoretically be more resistant to shine than their ABS counterparts. My experiences haven’t quite lived up to that expectation. Even after around two weeks of intense usage, I can already see shine starting to occur on my WASD keys and the spacebar. The texture is still there, so it isn’t a huge issue… yet. But I would love the texture to last longer than that.
Still, the pairings of switches and keycaps are one of the better parts of the K3 HE. They feel good to type on: the tactile response is tight and controlled, the switches are quiet, and the keys themselves feel nice underneath your fingers. As soon as you start to notice shine on the keyboard is the moment that experience goes downhill. Unfortunately, I am noticing it a little too early in my review. However, shine aside, the K3 HE offers a smooth, refined experience you don’t normally see from a keyboard this thin.
Battery Life and RGB
RGB on the keyboard is on the dim side. Paired with keycaps that don’t shine through, they don’t give off that blindingly intense gamer look you may expect from a magnetic board. Frankly, I think that’s well-suited for the K3 HE. The whole vibe of the keyboard is toned down and sleek, and the lower-impact lighting does not clash with the wood side accents.
All the necessary effects are present, and can be adjusted either in Keychron Launcher or via shortcuts from the keyboard itself. Brightness can be set from the keyboard as well. The illumination works just fine, but it is nothing to write home about. RGB is not something that will sell you on the board any more than it will dissuade you from buying it.
I may pick up a set of low-profile translucent PBT keycaps down the road, though. Something like that could help the RGB pop just a bit more without ruining the pristine appearance.
Battery life is powered by a built-in 2,600 mAh rechargeable lithium-polymer battery. Keychron advertises up to 55 hours of continuous wireless usage, but your mileage will vary based on connection method, RGB usage, and more.
In my experience, I was able to go about five full days with the RGB on full blast. Again, that’s nothing exceptional, but it’s decent for what is a rather slim-trim tri-mode magnetic keyboard. However, keep in mind that the K3 HE works with a 1,000 Hz polling rate when connected wired or over 2.4 GHz. It does not ramp up to 8,000 Hz like some folks might have expected. I would not by any means call the battery life outstanding because of this. It’s adequate for day-to-day usage and easily manageable, but Keychron could improve it in future iterations.
Software
Keychron keyboards are configured using their web-based Launcher configurator, and it’s a hub where you can customize not only your keyboard, but also Keychron's other peripherals (mice, for example). Launcher isn’t necessarily on par with Wooting’s excellent software suite just yet, but it is among the best-in-class tools for gaming keyboards — likely the top five. It’s a surprisingly capable platform that launches directly in your Chromium-based web browser with no strange downloads or needless installations. The layout is clean and intuitive, too. That should also go without saying, but it’s far from a guarantee in this space.
The keyboard is built around open-source QMK firmware, which opens the door to extensive customization. Key remapping, macros, shortcuts, and layer-based setups can all be tailored to your needs, giving the K3 HE plenty of flexibility beyond its gaming-focused features.
What’s there?
* Per-key Rapid Trigger and actuation-point adjustment
* Full key remapping
* Layer management
* Macros
* RGB customization
* Firmware updates
* Built-in testing utilities
Everything I’ve wanted is accessible from Launcher’s responsive single-panel interface. Tuning your actuation points feels intuitive and precise. You can configure each key individually, or lock settings across all keys to rapidly apply the same customization board-wide.
Layers also support Dynamic Keystrokes, along with a host of other gaming-centric features. With Launcher, you can easily create shotcalling layers optimized for FPSes or remap commands that are inaccessible or unintuitive to reach on a compact 75% keyboard.
The Launcher also extends beyond customizing how your keyboard functions. The K3 HE supports both SOCD and what’s popularly known as Rappy Snappy, although Keychron refers to each feature by different names. SOCD is replaced with Last Key Priority, while Rappy Snappy becomes Snap Click. Both features should come in handy if you play competitively in any title that demands rapid directional inputs.
RGB reacts live as you make changes, macros are intuitive to write, and you can even flash new firmware through the Launcher itself. It also supports 27 different languages. I kid you not, I’ve never seen that before in this category.
Keychron also offers Analog Mode in Launcher, a feature that enables the keyboard to input controller-style variable triggers. You could use Analog Mode in a racing game to more naturally control steering and throttle inputs, for example. Support for analog input is limited right now among other brands. Actually, shipping an analog mode that works properly is even more rare. To date, only a few companies offer it. Several competitors have analog modes in development, but we’ve yet to see them in public testing.
Every customization I could imagine is supported in Launcher, but there are a couple of minor issues. The software occasionally does odd things, particularly when connected wirelessly. The launcher also prompted me to flash the keyboard’s firmware and update the USB-C dongle to prevent future issues, despite Keychron explicitly telling me that neither of those steps would be required — that’s probably because not all models are supported in wireless mode.
Moments like these could frustrate novice users. Hopefully, these small bugs get worked out before too many people start experiencing them, as I saw frequent updates in the Launcher’s change log.
The good news is that firmware updates are easier than they were on the last Keychron board I reviewed. I no longer had to hold down a tiny button lurking beneath the keyboard’s spacebar to force the board into firmware-update mode. Weirdly enough, the button is still there, but it serves no purpose during firmware updates now.
Notable omissions include Mod-Tap support, which I hope to see implemented in a future software update. Launcher also only works with Chromium-based browsers. Still, it’s a modern tool that loads quickly and feels genuinely useful. Launcher is one of the better software solutions available these days, and it lays great groundwork for the brand’s competitive future.
Latency and Gaming Performance
The K3 HE feels good in-game. During my testing, I never encountered any weirdness, discernible lag, signal cut-offs, or missed inputs. I never had any reason to doubt that the keyboard would register my input while gaming. The only occasion where something didn’t go quite as intended was when I briefly switched to 2.4 GHz wireless mode, and my profile didn’t load properly. Consider it behavioral nit-picking rather than a critique of its performance, but this one time, it gave me some issues.
The Ultra-Fast Lime Low-Profile Magnetic switches feel great. They’re fairly accurate and fast, though the name is slightly misleading as they’re not all that light. There’s a bit more resistance than what I’m used to on other magnetic keyboards, but they still snap back fast and feel crisp. I actually prefer the slightly heavier feel myself. It strikes a nice balance between being light enough not to feel sluggish but still giving you plenty of control.
Latency measured at around 3 ms when wired, and about 3.5 ms when using the 2.4 GHz wireless dongle. You really cannot notice that small a difference when gaming. Wired and wireless act pretty much identically- the K3 HE has gorgeous latency numbers in either configuration.
On that note, the K3 HE does not have an 8,000 Hz polling rate option. The keyboard is set to poll at 1,000 Hz while wired or wireless connection. Bluetooth only supports 125 Hz polling, which is going to be horrendous in games, so treat that as more of an auxiliary connection for office use or hooking up the keyboard to other devices.
Especially since wireless is one of your primary reasons for purchasing this over the wired-only NuPhy Air HE lineup. Keychron has retained truly competitive performance while delivering on the promise of having a portable tri-mode keyboard. That’s a big deal because low-profile keyboards naturally have an advantage in gaming. Shorter key-travel and less distance to physical actuation make them feel faster out of the gate, even without Rapid Trigger. K3 HE builds upon that with custom adjustable actuation, Rapid Trigger, and TMR sensing.
Summary
It’s not perfect, but once you know what it’s trying to do, the Keychron K3 HE is easy to love.
Its strongest selling point isn’t any particular benchmark or fancy software feature. It’s simply the fact that this keyboard occupies an incredibly small niche. Low-profile magnetic keyboards are still exceptionally rare. To my knowledge, the only real competition at the moment is the NuPhy Air HE series, which are wired-only boards. Keychron adds full tri-mode connectivity to the formula, including genuinely usable 2.4 GHz wireless, while also swapping out a conventional Hall Effect sensor for TMR sensing.
That makes the K3 HE one of the most versatile keyboards you can buy right now. It’s slim, portable, and elegant enough to bring out for daily use, but offers enough of the features you’d expect from a modern gaming keyboard: adjustable actuation, Rapid Trigger, Last Key Priority, Snap Click, Dynamic Keystrokes, and Analog Mode. Measured latency is low across the board, and the difference between wired and wireless is negligibly small.
Admittedly, the implementation isn’t perfect. The polling rate is capped at 1,000 Hz instead of 8,000 Hz. Battery life is… fine, but not amazing. RGB brightness is fairly lackluster. Launcher is a polished suite of genuinely useful features, but it still has a couple of odd wireless-related issues that Keychron will hopefully smooth out in the future.
TMR also shouldn’t be viewed as some kind of magical bullet. On its own, it doesn’t automatically improve latency, and the K3 HE isn’t completely Mag- Mech compatible. You still can’t install one magnetic switch alongside a traditional mechanical switch on the same PCB. It does make sense for a portable wireless keyboard, though. Low power usage, high sensitivity, and the potential to do even cooler things in the future are all big pluses for TMR.
Build quality is similarly strong, if not *quite* at the premium level of something like the IQUNIX Magi65 Pro. I love the wooden side panels, restrained RGB lighting, and overall minimalist aesthetic. The K3 HE has a warm, cosy vibe to it that feels worlds away from the intentionally aggressive styling of so many other gaming keyboards.
That’s the K3 HE in a nutshell: it’s not going to be the right keyboard for absolutely everyone. It’s not for the person who absolutely needs the highest polling rate possible, or wants the fanciest premium materials their budget will stretch to. It’s for the person who wants a compact, low-profile magnetic keyboard that’s equally great for gaming, typing, and wireless use.
And for that person, it’s hard to look past. If you’re in the market for a low-profile magnetic keyboard, the Keychron K3 HE absolutely deserves to be on your shortlist.
Bullet Points
- One of the very few low-profile magnetic keyboards…
- …and the first TMR one
- elegant look, cosy wooden vibes
- This keyboard is very well priced for what it offers
- quiet and comfortable sound profile
- very low typing angle out of the box (can be adjusted with feet)
- Ultra Fast Lime low-profile switches are heavier than you would expect
- Good software that acts as a hub now (Keychron Launcher) with some small issues, though
- low latency despite 1000 Hz polling rate
- It’s not fully Mag-Mech as you would expect from a TMR keyboard
- good overall build quality
- very portable and light
- average battery life
- dim RGB (solid PBT LSA keycaps)
- strong recommendation for low-profile gaming keyboard lovers
Get Keychron K3 HE
Disclaimer
This review is not a paid endorsement. I want to ensure transparency and let you know that I am not receiving any monetary or other compensation for evaluating or discussing this tech product. Certain images might have undergone digital enhancement to improve visual clarity. These adjustments do not alter the product’s true appearance, shape, or physical characteristics.
