Build Quality
Overall build quality is mostly solid. Much like on the DM6 Holey S, shaking the mouse has a minor rattle come from the buttons for polling rate and lighting located on the bottom. Additionally, the sensor lens is loose on my sample, resulting in major rattle. When applying lateral pressure, no creaking or flexing of the shell can be observed, but squeezing the sides with excessive force may activate the forward side button. Lastly, no accidental clicks occur when slamming down the mouse.
Main buttons on the DM6 Holey Duo are very good. Both pre and post-travel are low, resulting in a firm and satisfying button response. Click feel is slightly dull, however. The buttons are separated from the shell, yet lateral button movement is as low as physically possible. Button stiffness is light. Huano switches (blue shell, white plunger) are used.
Side buttons are very good. Both pre and post-travel are low, resulting in a snappy click response. The pressure point isn't entirely even across the entire button, resulting in a somewhat spongy feel, particularly on the forward button. Button size and placement is good as actuation is possible rather easily by rolling one's thumb across. Another set of Huano switches (yellow plunger) is used here.
At the top of the mouse is a single button for cycling through the set CPI levels. Its click feel is good. Yet another Huano switch (yellow plunger) is used for this one. Two buttons found on the bottom of the mouse control lighting and polling rate—they work fine as well.
The scroll wheel is good. Scrolling down barely produces any noise, but scrolling up does. Additionally, scrolling is very light, providing hardly any discernible steps and below average tactility overall. The encoder comes from F-Switch. The middle (scroll wheel) click requires medium force for actuation. Unsurprisingly, another Huano switch (white plunger) is used here.
Coating
The DM6 Holey Duo has a smooth matte coating all over. Grip is fine, but it's an absolute fingerprint and oil marks magnet. Merely touching the mouse leaves permanent marks. Even the most diligent cleaning won't ever get entirely rid of these. All in all, a poor coating.
Disassembly
Disassembling the DM6 Holey Duo is very easy. Just remove the two rear mouse skates, unscrew the screws, and pop the top and bottom shells apart (the former is clipped in at the front). The internal design is equally simple. Everything sits on a single PCB; that is, except for the side buttons on their own PCB mounted vertically and connected to the main PCB through a 3-pin JST connector. The main PCB is surprisingly large and moderately thick, and held in place by three clips and several pins instead of screws. The MCU is a Sino Wealth SH68F 1000S. Please refer to
this for more information. Production date for the main PCB is the 45th week of 2020.
As for the soldering and general quality of the PCB, I'm unable to find any noteworthy flaws.