The Zowie Celeritas II is a bit of a rarity in the mechanical keyboard world because it’s one of the few gaming keyboards that doesn’t use Cherry MX-style switches. Instead, it uses Flaretech optical key switches made by Taiwanese manufacturer Adomax to Zowie’s specifications. You might recognize these switches from the Wooting One Kickstarter keyboard that came out in 2016.
Like Cherry MX-style switches, Flaretech optical switches also consist of individual switch modules mounted in a metal plate over a printed circuit board. However, there are no electronics in the switch modules themselves. Instead, surface-mounted infra-red optoelectronic components on the circuit board provide the sensing in conjunction with a prism in the switch slider. The optical sensor allows for a much faster confirmation of the keypress with a debouncing rate (the amount of time it takes for the key to settle) of just 0.03ms. To compare, Cherry MX switches have a debouncing rate of about 5ms. The only type of switch with a lower debouncing rate is a capacitive switch (i.e. Topre). In practice, this is mostly unnoticeable, but it’s nice to know that your keystroke technically confirms faster than the average joe using a Cherry MX board.
The other interesting aspect of optical switches is that they allow for analogue key travel. In other words, the optical sensor can read how far the key is depressed, and output a different result based on that. Having said that, while the Wooting One uses this feature, the Celeritas II does not, and it only reads on/off input.
Despite its exotic switch technology, the Celeritas II doesn’t actually feel that different from a standard Cherry MX-style keyboard. The switches are linear with a very smooth feel and a relatively short travel distance. They're smoother than Cherry MX Reds, but with a heavier actuation force – somewhere between Reds and Blacks. Unfortunately Zowie won’t disclose the exact specs of its switches, so I don’t have any numbers to compare. The closest comparison for me would be slightly stiffer lubed Gateron Reds. Adomax lists its Flaretech linear red switch at 55g, with an actuation point of 2-4mm and a travel of 4mm. While Zowie says its switches are made to its own specifications by Adomax, that sounds about right for the Celeritas II (only with a fixed actuation point of 2mm instead of the variable 2-4mm).
Zowie says that one of the benefits of an optical switch is that it eliminates double-pressing. Personally, I've never encountered this problem with any of my Cherry MX keyboards, or even any MX clone switch, so I can't say that it's an issue I'm concerned with. If it is something you've had an issue with in the past, you might value this aspect of the Celeritas II more.
The keyboard is full-sized, with a matte finish, and red backlighting. There’s a small built-in wrist rest that is basically useless. It’s not large enough to rest your wrist on, but it’s too big to use your own wrist rest.
Multimedia function keys and backlight brightness controls can be accessed with an Fn key modifier. There are no dedicated LED indicators for the Scroll, Num and Caps lock keys, instead the backlighting changes from red to blue when they’re activated. I actually didn’t realize this at first because I had the backlighting turned off completely.
While the keyboard uses standard Cherry MX stems, it has a non-conventional layout that makes keycap replacement tricky. It uses an irregular ‘big-ass’ backwards L Enter key, and a short right shift to make space for a relocated backslash key.
The keycaps themselves use standard/OEM profile sculpting and are made from black painted ABS with translucent legends to allow the backlight to shine through. As you can see from my review unit, the keys absorb oil from your fingers fairly easily - for the record I'm not the first person to use this keyboard, so I can't say for sure how long it takes for the keys to look this grubby.
There are no feet on the bottom of the keyboard, so you can’t adjust its height, but it has a fairly comfortable gradient that should suit most people.
The keyboard is hard wired in the centre of the board. The cable is the soft flexible type that Zowie also uses on its mice. For mice, these cables are great because they're lightweight and won't kink, but on a keyboard, this isn't really a factor since you won't be moving it around. As such, I would have preferred a removable cable or a more robust braided cable instead.
Like all of Zowie’s products the Celeritas II is driverless and plug and play. It uses a standard USB connector, but the Celeritas II also has PS/2 support via an included adaptor. Theoretically, PS/2 keyboards are superior to USB keyboards, because they aren’t limited by USB polling rates, and instead send an interrupt signal the instant an input is activated. USB keyboards also have to share bandwidth with other connected USB devices, whereas PS/2 protocol acts independently of them. Once again, in practice, this is mostly unnoticeable, but it’s nice for peace of mind.
From a purely technical standpoint, the Celeritas II is one of the best gaming keyboards you can buy. For min-maxers that want any possible advantage they can get, the Celeritas II’s optical switches and PS/2 support offer the lowest possible latency you can get from a keyboard. Having said that, personally, I didn’t notice any difference in game between the Celeritas II and my regular Vortex Pok3r with Cherry MX Reds.
Additionally, at an SRP of S$209 the Celeritas II is quite expensive for what you get. You're basically paying a premium here for the Celeritas II's exotic optical switches, because there aren't many other features to speak of. At this price range, you generally get RGB backlighting and some dedicated macro keys.
All things considered, while I really like the ultra smooth switches on the Celeritas II, I dislike the massive form-factor and unusable wrist rest. Unlike gaming mice, I don't notice much difference in in-game performance when switching from keyboard to keyboard, so comfort and feel become the most important things for me. For me personally, the Celeritas II is just too big to use comfortably. I don't use the numberpad, and the full size form factor means that I either put the keyboard at an angle or have my hands really far apart, which results in poor ergonomics.
One of the things I love about Zowie mice is that they all come in different sizes to best suit your hand-size. Unfortunately, that isn't true of Zowie's keyboards as the Celeritas II is only available in one size. If Zowie made the exact same keyboard but offered it in a compact 60% or tenkeyless form factor, and with a minimal bezel instead of a built-in wrist rest I would be highly tempted to switch to it. If it used a standard layout too, consider me sold.