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 do not occur unless debounce time is set to 0 or 1 ms.

Buttons

Main buttons on the M3S Varun are good. Pre-travel is moderate and post-travel low, resulting in a fairly firm and snappy button response. While the buttons are visually separated from the shell, lateral button movement is quite low even when provoked. Button stiffness is medium. A pair of TTC Gold (60 M) switches are used.


Side buttons are good (back button) to very good (forward button). Both buttons have low post-travel, but the back button has significant pre-travel, coupled with uneven actuation. Button size and placement are good, as actuation is possible rather easily by rolling one's thumb across. A set of TTC switches (red plunger) is used for these.

At the bottom of the mouse is a button for cycling through the set CPI levels, which works just fine. A seemingly unbranded tactile switch is used for this one. An additional button cycles through the available polling rates, which too works fine. Another seemingly unbranded tactile switch is used for this one. Lastly, a slider at the bottom switches between 2.4 GHz operation, Bluetooth, and off-state, which also works fine.

Scroll Wheel

The scroll wheel is decent. Noise levels are elevated, and the wheel also emits a rather irritating creaking sound when scrolling up, which adds to the cheap impression. Tactility is average, as the individual steps are only moderately separated from each other. The encoder comes from TTC (yellow or "Gold") and has a height of 10 mm. The middle (scroll wheel) click requires medium force for actuation. What appears to be an Omron D2FC-F-7N (20M) (OF) switch is used for this one.

Surface

The M3S Varun 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.

Button Sound Test

Disassembly

Disassembling the M3S Varun is easy. After removing the front and rear skates along with the screws beneath them, two additional clips on the left and right side need to be dislodged as well, which is most easily done by wedging a credit card (or similar) in between. Afterwards, the top and bottom shell can be separated, but make sure not to rip the cable connecting the PCBs when doing so.

The internal design is efficient. The side buttons sit on their own PCB screwed to the top shell and connected through a ribbon cable to the main PCB. Everything else sits on the thin main PCB, which is affixed to the bottom with four screws. An auxiliary PCB vertically mounted onto the main PCB provides wheel illumination. The MCU is a Telink TLSR8273, whose datasheet is found here. Production date for the side-button PCB is the 21st week of 2023.


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