The GK66 promises a lot of stuff. It’s fairly affordable, A bluetooth 3.0, mechanical keyboard with swappable switches sounds too good to be true, isn’t it? I feel that a straight out of the box only review for this particular board wouldn’t be sufficient, since most of us would buy this board so that we can use different switches, and possibly keycaps as well. So I sourced some replacement switches and keycaps

What’s in the box

Inside the cardboard box you’ll find the GK66, a braided, gold plated USB-C to USB-A cable, a couple of optional keycaps if you want to use a Mac layout, a keycap puller, a metal switch puller, and 2 spare red Gateron optical switches, a black and a blue switches

Build Quality

The GK66 all-plastic construction feels light but quite sturdy. The keycaps are not bad at all, I’d say they are comparable with the ones that come with my Razer Blackwidow Elite.  The switches are plate-mounted, and since they are being held in place just by friction, some of the switches got pulled when I tried to replace the keycaps. The included keycaps for the spacebars are a bit sloped. You can’t adjust the inclination of the keyboard as it doesn’t provide adjustable feet. The metal plate keeps the overall construction sturdy and rigid.


Powering up and down the GK66 are done by pressing the 6x/Fn+Left Tab buttons combo. Just like Royal Kludge’s RK61, you can use Bluetooth 3.0 to wirelessly connect the 750mA battery powered GK66 to 3 devices. Switching between bluetooth connection takes 3 to 4 seconds. You can also switch the GK66 to wired mode by pressing the 6x/Fn+Z key combo, and connect the keyboard into your system with the included USB-C to USB-A cable.

The GK66’s onboard memory allows you to store up to additional 3 profiles/layers of key mappings, aside from the default one, so you can configure the board in Windows, which is the only operating system supported by the GK6XPlus software, and then use these settings on your linux box

As do most enthusiast “toy” nowadays, the GK66 features RGB lighting. You can cycle through the available effects right on the keyboard by pressing the 6+/Fn+[, or 6+/Fn+]

Swapping Switches

Unfortunately, if you have a set of favorite switches, you probably can’t use them with GK66. Instead of pins that we usually find on traditional PCBs, each socket of GK66’s board is equipped with a pair of IR sensors that are communicating to each other when they are in line of sight, which is when the switch is not pressed. When we press a key, the stem on the switch comes down, blocking the communication between these sensors, and tells the board that this particular key is being pressed. Since the board lacks traditional pins, thus the only compatible switches that you can use with the board are Gateron Optical switches, which as of now, come either in linear red, black and silver linear, as well as tactile blue, green, and brown.

As of today, the only place that I find in the internet that sell these switches is EPathBuy, and fortunately they are reasonably priced. It took about 30 days for my pack of 70 Brown optical switches to reach my doorstep since I decided to get the cheaper epacket delivery option.

Swapping keycaps

Swapping keycaps is similarly problematic. If you’re planning to to swap GK66’s pre-installed keycaps with something different, make sure you have a set that has:

  • 2u left-shift
  • 1u right-shift
  • 2.75u and 2.25u for the split spacebars
  • 1u for mouse right click context menu, and
  • 1u right-alt

To have all of these, you might have to kitbash a couple of  keycap sets into one. I find that the easiest way to do this is by starting with an ANSI 61/64/68 combo set such as this Minila/Tada68 combo or this XD60/XD64/GK64 combo set. These will usually give you all the keycaps that you need except for the 2.25u and 2.75u spacebars and sometime the 1u context menu. You can order those from some store on Aliexpress that do customized sets such as this one. Or, if they don’t sell your choice of keycap profile, alternatively you can get a set of blank modifier keycaps for standard ANSI 104 keys, as the left-shift and right-shift combo is exactly 2.25u and 2.75u. I got mine from the Aliexpress store that sell me the GK64/Tada68 combo for USD0.5 each. It usually takes around 2 to 4 weeks for you package to arrive if you choose the default aliexpress packet delivery option. Here’s how my GK66 after some makeover, along with the RK-61. The arrow keys are from Tai-Hao’s neon rubber keycap set. While the GK66  packs dedicated arrow keys, it’s actually only a wee bit larger than Royal Kludge’s RK61. The GK66 manages this by reducing the size of the right Shift key, which I almost never use anyway

In Use

My main problem with RK-61 is that it doesn’t have dedicated arrow keys. On RK-61 “/”, “?”, and “” share the same key. As a linux user and SysAdmin, I use all three quite often. The GK66 resolve this issue. and it works quite well.

One of the most important thing on compact keyboard is button mapping. Losing nearly half of the buttons on your keyboard means you need to be able to prioritize which buttons are available on the keyboard, and which functions are relegated to the Function layer. The GK66’s software does well for what I need, which is remapping the left-Shift button to Left-Ctrl. Aside from the standard non-customizable configuration, the onboard memory allows a total of 3 additional layers of custom key mappings to be stored on the keyboard itself, allowing you to configure the GK66 in one computer and use it on other without installing the software. I was able to plug the GK66 to my Windows 10 VM to remap the Left-Shift to Left-Ctrl, and use it later in my Ubuntu host. Switching between these layers are done by pressing the combo of 6+/Fn and either W, E, or R, respectively for layer 1, 2, or 3. Pressing 6+/Fn and Q will return you to the standard layout.

Switching between bluetooth-paired hosts, which is done by combining 6+/Fn key and either Z, X, or C, takes about 3 to 4 seconds. I’m not a fast typist, so latency, IF it exists, is manageable. Sometime it feels like the keyboard misses keystrokes, but I can’t really tell 😀

Typing on a compact keyboard is always a challenge for me. One thing to note is that in the default layout the GK66 does not have right Ctrl button. It might not seems like a big deal, right? Well, most likely yes, unless you’re a sysadmin for VMWare ESX, or Virtualbox, as the default host key for disengaging your keyboard from  guest console window is exactly the right-ctrl key. I ended up mapping the right-shift button to right-ctrl, which bring us to another issue with the keyboard, which is the software.

In overall, the Microsoft Windows-only driver and software UX is a messy experience, as even the english version of the software still uses Chinese for some part, such the dropdown list for the lighting effects available for the action that I’m configuring. And I practically gave up trying to set macro.

One of GK66’s main attraction is the swappable switches, and swapping them is easy. I used to be an avid cherry mx red user, but lately I’ve been gravitating toward clickier switches such as the Razer Green that comes with my Blackwidow Elite. As such,  I opted for the Gateron Optical brown for my second set of switches. The included metal switch puller works well, and installing a new switch is as easy as pushing them into the socket. Since the switches are kept in place only by a small plastic tab at the upper and lower portion of switch case, regularly pulling and installing them is not recommended.

And lastly, the battery life. While the capacity is only a little bit smaller than RK61, the GK66 fails at standby time. While the GK66 never crapped on me if I use for hours after a full charge, the battery is completely drained after I leave it turned off for more than a day. I have a suspicion that lack of proper power switch has become the downfall of GK66.

Final Thought

So here’s the thing. I like the board very much, more so when I swap the switches to the brown one. But recommending them for purchase is whole different discussion. The unfortunately limited compatibility to only Gateron Optical switches basically eliminate the potential for the GK66 to be your choice for switch testing board. For daily use, if you are already familiar with typing on compact sized keyboard, these Gateron switches is perfectly fine. Another issue with the board is the clunky software. The biggest issue for me is the abysmal stand-by time that prevents me from recommending it as a traveling companion.

If you use the GK66 as a main keyboard for your workstation and consider the bluetooth function as a bonus that you don’t use often, the GK66 is an excellent choice. But at the end of day, while the GK66 is an exciting board, there’s actually no usage-scenario it’s excelling at, which is unfortunate, as I really enjoy typing with it.

Verdict: 3/5

By ikhsan

2 thoughts on “Review: GK66 Bluetooth Mechanical Keyboard with Swappable Gateron Optical Switch”
  1. I have two questions. Can this right part of the space be set as right alt? There is a number 3 in the software photo. The second question is whether the keyboard starts in the mode as it was turned off or in the standard mode?

    1. Sorry for the super late reply. To answer your question, yes, I tried mapping the right space as Right-Alt in one of the layer and it worked. As for your second question, yes, it will start in the previously active layer. The latest version of the software is so much better than the one that I used at the time of this post was written. You can download it and all of the previous releases here

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