Build Quality
Overall build quality is very solid. There is no rattle when shaking the mouse. When applying lateral pressure, no creaking or flexing of the shell can be observed. Activating the side buttons by squeezing the sides is impossible. Lastly, accidental clicks when slamming down the mouse only occur if debounce time is set to 0 ms.
Main buttons on the Model O 2 are very good. The left button has moderate pre but very low post-travel, whereas the reverse is true on the right button. Button response is very firm and snappy nonetheless. Despite being visually separated from the shell, button movement is low even when provoked. Button stiffness is medium. A pair of Glorious-branded switches, which are modified Kailh GM 8.0 (80 M), are used here.
Side buttons are good. Post-travel is low, but the back button in particular has noticeable pre-travel, resulting in a somewhat mushy button response. The actuation point is mostly even across the entirety of these. Button size and placement are quite good, as actuation is possible rather easily by rolling one's thumb across. A set of Huano switches (green plunger) is used for these.
At the top of the mouse is a button for cycling through the set CPI levels, which feels decent. Another Huano switch (green plunger) is used for this one.
The scroll wheel is excellent. Noise levels are appreciably low, and tactility is very good, providing clearly separated steps and controlled scrolling. The encoder comes from F-Switch (yellow, green core) and has a height of 11 mm. The middle (scroll wheel) click requires medium force for actuation. Yet another Huano switch (green plunger) is used here.
Surface
The Model O 2 has a matte surface all over. Grip is fine, and it doesn't attract fingerprints or dirt too much. It is easy to clean, and there are no signs of wear left after doing so. All in all, excellent materials.
Disassembly
Disassembling the Model O 2 is reasonably easy. First, all skates as well as the screws beneath them need to be removed. Top and bottom shell are readily separated now, but some caution is advised to prevent ripping any cables.
Tooling is shared with the Model O 2 Wireless, which somewhat limits the efficiency of the design. The top and side buttons sit on their own PCB screwed into the top shell and connected through a ribbon cable with the main PCB. Likewise, the left and right-side LED strips are connected through ribbon cables, too. Everything else sits on the relatively spacious main PCB, which has been affixed to the bottom with three screws. The MCU appears to be a rebranded Westberry WB32F103C9T6, whose datasheet can be found
here. The production date of all PCBs is the 44th week of 2022.
As for the soldering and general quality of the PCB, I'm unable to find any noteworthy flaws.