Build Quality

Overall build quality is mostly solid. A rattle comes from the main buttons when shaking the mouse. When applying lateral pressure, the side walls can be pushed in quite easily, but there is no noticeable creaking or flexing to speak of otherwise. Activating the side buttons by squeezing the sides is possible even without using excessive force. Lastly, when slamming down the mouse, the main buttons, scroll wheel switch, and even scroll wheel itself may actuate or be enabled occasionally.

Buttons

Main buttons on the X12 are good. There is some pre and post-travel, but button response is snappy and pleasing nonetheless. The bigger issue lies with the buttons being somewhat loose. While lateral play is limited, the buttons do move slightly under the fingers, and when shaking the mouse, a rattle accordingly becomes audible. Button stiffness is light. A pair of Omron D2FC-F-K (60 M) (China) switches is used.


Side buttons are good on either side. The back button has some pre-travel, but post-travel is low on both, resulting in a firm and snappy button response. The pressure point isn't entirely even, however, especially on the back button. Furthermore, their placement is somewhat questionable. They sit a bit lower than expected, which is exacerbated by their smaller size, and the space between the buttons and thumb rest is rather limited. As a result, the set of side buttons on the opposing side may also get in the way during use. Two sets of Kailh switches (orange-ish plunger) are used for these.

At the top of the mouse is a single button for cycling through the set CPI levels. Its click feel is decent. A seemingly unbranded tactile switch is used for this one. At the bottom of the mouse is another button for cycling through the available profiles, which too works fine. Another seemingly unbranded tactile switch is used for this one.

Scroll Wheel

The scroll wheel is decent. Scrolling up in particular is noisy, and tactility severely lacking, as the individual steps are barely separated, leading to exceedingly light scrolling. The encoder comes from TTC (gray, gray core) and has a height of 12.6 mm. The middle (scroll wheel) click requires medium force for actuation. A seemingly unbranded tactile switch is used here.

Coating

The X12 has a smooth matte surface all over. It doesn't attract fingerprints, dirt, or the likes too much and is easy to clean, and there are no signs of wear left after doing so. All in all, excellent materials.

Button Sound Test

Disassembly

Disassembling the X12 is easy. First, all skates and the screws beneath them ought to be removed. Top and bottom shell then can be separated with ease.

The internal design is equally simple. The top and side buttons sit on their own PCB screwed into the top shell and connected to the main PCB through a 6-pin connector. Everything else sits on the main PCB, which is affixed to the bottom shell with four screws and very thin, whereas the side-button PCB is moderately thick. The MCU is an NXP LPC5516, whose datasheet can be found here.


As for the soldering and general quality of the PCBs, I'm unable to find any noteworthy flaws.