MX ULP remains one of the most interesting mechanical keyboard innovations I've used, yet it's baffling why the industry never ran with it.
Back in 2022, I reviewed a keyboard that I still think about more than most hardware that's passed through my hands since. The Corsair K100 Air Wireless was, at the time, one of the most expensive keyboards I'd ever tested, and I said as much in my verdict, but I also called it one of the best keyboards I'd used full stop, and I meant it. What made it special wasn't necessarily its RGB, the iCUE software, or even the versatile wireless connection on offer.
It was its clever Cherry MX Ultra Low Profile switches. Several years on from my first look, that same technology still hasn't gone mainstream, and dusting the K100 Air Wireless off again is a good reminder of exactly what's been left on the table.
It's worth saying upfront that "slim" gets used as a catch-all term far too often in this industry, lumping together products that are actually solving quite different problems. A low-profile keyboard and an ultra-low-profile one sound like a difference of degree, a few millimetres here or there. However, in practice, I think they're closer to two different categories of product that happen to share a marketing buzzword, and the K100 Air Wireless remains one of the best exhibitions of the technology to the point I'm surprised it's still so underappreciated.
What made the K100 Air Wireless different
The real kicker for the K100 Air Wireless was its inclusion of Cherry's MX Ultra Low Profile Switches. You might think I'm being facetious by saying that as low-profile mechanical keyboards aren't a new thing, but there is a vital difference between low profile and ultra low profile. Short low-profile switches, the kind you'll find in something like Corsair's own K60 RGB Pro Low Profile or Logitech's G915 X Lightspeed, are a meaningful step down from a full-height Cherry MX switch in size.
ULP switches work via a different design altogether to the usual mechanical switch mechanism that's just been downsized, using metal "wings" that pivot down onto the actuator rather than a plastic stem pushing straight onto a set of crosspoints. That mechanism let Cherry get the total switch height down to 3.5mm and total key travel to just 1.8mm, packed into a board only 17mm tall at its thickest point.
On paper, it doesn't sound like much, and to some it could be the recipe for a mushy keypress you'd hardly want to return to. This comes especially as the ULP switches were only available in tactile flavour, with either a bump or a click under finger, and 1.8mm of travel doesn't really leave much room.
However, it's the genius of these switches that it works beautifully. The tactile bump on Cherry's MX ULP Tactile switches is short and sharp rather than the rounder, more drawn-out feel of a full-height switch, but it's genuinely there, and genuinely satisfying. Even more surprising was the actuation force: at 65cN, these are about as heavy as one of my other favourites – the full-height MX Clear, which would normally leave your fingers fatigued over a long session. However, because the total travel of an MX ULP is so short, that fatigue never really materialises — your fingers simply don't have far enough to go for the extra weight to become a problem. It's a genuinely clever piece of engineering, and using it convinced me that ultra-low-profile was a feature to shout about in its own right.
Of course, none of this would have mattered much if the rest of the keyboard hadn't held up its end of the deal, and it has – wonderfully. At 780g, the K100 Air Wireless was still a substantial object despite its thinness, with an aluminium top plate that kept it feeling planted on a desk rather than skating around under a firm keypress the way genuinely lightweight and less well put together boards can sometimes do. Battery life, at around 50 hours, was more modest than Corsair's fuller-sized wireless boards, which is one of the honest costs of packing everything into such a thin chassis — there's simply less room for cell capacity once you've committed to 17mm, but it's still enough for a working week before charging.
Where the rest of the industry went instead
The advent of the MX ULP switch came at a time when the mechanical keyboard industry was at a bit of a crossroads, and manufacturers went in all sorts of different directions. The previous couple of years had seen an explosion of a new breed of keyboard hobbyists, buoyed by the extra time they'd had during the pandemic, and it became the job of mainstream manufacturers to tempt new folks into the hobby.
Some brands went the way of intersecting traditional gaming keyboards with more enthusiast-grade features, such as the Asus ROG Azoth, while others stuck to their guns with traditional mechanical products, such as Cherry. Elsewhere, it's roughly at this time we saw the beginnings of optical switches transition to Hall effect ones in the gaming space, complete with the application of adjustable actuation points and rapid trigger powers for the utmost speed. This is the path that seems to be most common for gaming keyboards, and is a lot of where the industry has headed.
Corsair is the only brand that took the approach of opting for an entirely new product category with the K100 Air Wireless, and it's so far remained one of the only brands that has offered an MX ULP keyboard in the mainstream.
For reference, Cherry has its own KW X ULP, an office-centric product without some of Corsair's gaming bells and whistles, alongside a smaller form factor, wireless KW X ULP 2.0 MINI I'm yet to get my hands on, and boutique manufacturer Mistel is still flying the flag with its gorgeous AirOne, with a small form factor layout, slender aluminium case and a choice of either MX ULP Click or Tactile, which is increasingly rare.
The fact is that thinness wasn't the fight anyone was having when the K100 Air Wireless was first released. The fight was over hot-swap versus soldered switches, over 60% versus full-size, over wired latency versus wireless convenience. MX ULP answered a question from an entirely different conversation if you think about it. The one laptop manufacturers were having about fitting a genuinely mechanical typing feel into an increasingly slim chassis — and that's arguably the real reason it never found its footing on a desktop outside of the admittedly niche examples. It wasn't competing for attention in the argument the enthusiast and gaming markets were actually having with each other. It was solving a laptop problem that happened to also make a genuinely excellent desktop keyboard, almost as a side effect, and the desktop crowd never quite worked out where to file it.
Laptops have been the only place where we've seen MX ULP switches outside of those select desktop keyboards, with Alienware, Medion and Corsair itself putting them into their most premium offerings to offer a much stronger and more responsive typing feel than any membrane or scissor-actuated keyboard could.
Things have begun to coalesce in more recent years, although not to the point MX ULP seems like it's hitting the mainstream any time soon. NuPhy's Air60 HE, released in late 2024, is the first mass-produced low-profile Hall Effect keyboard I remember seeing, built around Gateron's own Magnetic Jade low-profile switches. It's a keyboard I loved when I tested it elsewhere, where the combination of Hall Effect precision and a shortened low-profile travel made for some of the most responsive movement I'd felt from a keyboard in that specific size. Likewise, its software packed in an obscene amount of customisation for those switches to make it quite a small and mighty gaming powerhouse.
Now we're beginning to see that shift again, with brands moving towards TMR switches as the next iteration for the high power gaming keyboards of 2026. TMR has numerous benefits over Hall effect, with even greater precision at a lower power consumption, potentially solving the age-old problem of wireless Hall effect gaming keyboards having meagre battery life. That's all very well and good, but it seems like ultra low profile switches are being left in the dust from everyone.
Where MX ULP goes from here
The last thing I want to see is the MX ULP being left behind – it's far too good in any right to be lost in the noise of Hall effect, TMR, or even more standard mechanical switches, which seems to have been the case for the last couple of years.
I admit, things aren't perfect. With the way these switches are constructed, it isn't particularly easy to find any form of aftermarket keycaps for them, which limits any form of modifications the hobbyist community can do for ULP switches. Likewise, if you break a keycap, that's it – you can't necessarily replace it with ease.
The problem the K100 Air Wireless had was that it launched at £279.99 during a rotten cost of living crisis, making for about as unfriendly a moment as there's been in years for a premium-priced, hard-to-explain niche product to find its feet. Corsair has, in recent years, heavily discounted the keyboard at various points in time, making it one of the bargains of the century when it comes to a feature-rich and, quite frankly, unique gaming keyboard among its contemporaries, although even then, it's been hard to see any mainstream pickup.
I feel there is a way forward for MX ULP in a 'reborn' state as it were. The keycap problem is a stubborn one, but it's not unsolvable, and it's arguably less of a barrier than it was when the K100 Air Wireless first launched. Mainstream peripherals brands have gotten considerably better at treating first-party keycaps as a genuine selling point rather than an afterthought as they once were. PBT double-shot sets are now the expected default on anything positioning itself as premium. A serious ULP keyboard relaunch from any brand wouldn't need to win over the aftermarket keycap scene at all if it shipped with a genuinely excellent set out of the box and simply accepted that customisation would stay limited, the same trade a lot of low-profile laptop-style mechanical boards already ask buyers to make without much complaint in some respects.
As for the pricing, Mistel's AirOne has already shown ULP can be built and sold at a price much under what Corsair was charging. Okay, it doesn't have much of the software and connectivity benefits that make the K100 Air Wireless a boon for power users or the same brand recognition, but in any guise, £279.99 was a hefty sum to pay at the time.
A mid-range MX ULP board, priced to compete with the current wave of £100-150 Hall Effect keyboards rather than sitting above all of them, is a much easier thing for a cautious buyer to say yes to than a £279.99 experiment was several years ago. After all, with the democratisation of tech such as wireless connectivity and potent web-based software among an array of smaller manufacturers with more affordable wares to sell, it means there isn't as much of a premium attached to a full-spec keyboard as there once was.
Where this leaves us
The point to make is that none of this is a failure of engineering. The MX ULP switch is something that, on the evidence of my own time with it, is one of the best-feeling switch designs I've used in any format, full stop. It solved the tactility problem a shortened switch should have had, and it's still solving it in a handful of boutique boards years later. What it never got was the right moment, and the more I sit with it, the more I think that moment might finally be arriving.
The comparison with Hall Effect and TMR is instructive here rather than discouraging. Both proved something the mechanical keyboard market didn't know it was ready to hear – that standard mechanical switches weren't the be-all-and-end-all for gaming. Buyers would pay a premium for switch innovation if it meant things would go faster, such as adjustable actuation or rapid trigger. MX ULP never got that hook because it's perhaps a much harder pitch thana headline feature on a spec sheet, and needs to be felt rather than read to land.
I've always maintained keyboards are something to be felt for you to get the best fit, rather like Ollivander's in Harry Potter – let the keyboard choose you. It just so happens with the demise of retail and such that it's becoming even harder to do so at a time when the mechanical keyboard industry is one of the most interesting it's ever been, but that's a different argument for a different day.
Looking back at the K100 Air Wireless now, it's striking how little competition it's actually had to answer to in the years since. A keyboard that good, at a technology that novel, should have prompted a wave of rivals the way Hall Effect and now TMR boards now answer to each other constantly. Instead it's mostly answered to laptops, and to a handful of boutique boards most buyers will never encounter outside a dedicated keyboard forum. And that's the great shame – you have to look to find this innovation.
I went around the show floor of Computex 2026 with a fellow journalist a couple of months ago, pointed out the Mistel stand, and he tried the AirOne, which seemed like a revelatory moment – a "why have I never tried or heard of this before?" moment, and that's exactly what needs to occur with MX ULP in a more general sense. If people could actually feel the benefit, then it might make these ultra-low-profile switches a much easier sell.
I'd love to see a mainstream brand – Corsair included, given it already owns the exact review that proved this could work — take the bet a second time, at a more sensible price, with the keycap and pricing lessons the rest of the industry has quietly worked out since sitting right there for the taking.
After all, Hall effect and TMR have both proved the appetite for genuine switch innovation exists as long as it's marketed in the right way. MX ULP has proven things work brilliantly, but it just seems to need more of a push than the rest of the industry is willing to give it. Someone just needs to be brave enough to bring those lessons together on a single desktop board, priced sensibly, rather than leaving MX ULP to fade quietly into the laptops and niche boutique runs it's been confined to for several years.
Going back to the K100 Air Wireless and its contemporaries for this piece reminded me how good "genuinely thin and genuinely satisfying to type on" can feel when someone actually commits to building it properly. That's a lesson worth learning twice, and I hope we don't have too long to wait before somebody finally does.
Reece Bithrey is a twenty-four-year-old freelance journalist who reviews and writes about shiny things for a living. He's been featured in Trusted Reviews, PC Gamer, PCGamesN, Custom PC magazine, TechRadar, Eurogamer and The Guardian. He also has his own blog, UNTITLED. He is a mechanical keyboard nerd, so you'll usually find him tinkering there when not writing, or bellowing at virtual footballers on Football Manager.