Build Quality

Overall build quality is solid. When shaking the mouse, a rattle comes from an indeterminable location. When applying lateral pressure, no creaking or flexing of the shell can be observed. Activating the side buttons by squeezing the sides is possible, but requires excessive force. Lastly, accidental clicks when slamming down the mouse do not occur unless Button Response Optimization is disabled within iCUE.

Buttons

Main buttons on the M75 Air are good to very good. Pre-travel is moderate, whereas post-travel is low. Button response is fairly snappy, though also a bit dull and muted. Despite being visually separated from the shell, button movement is fairly low even when provoked. Button stiffness is medium. A pair of TTC optical switches are used.


Side buttons are very good. Both pre and post-travel are low, resulting in a snappy button response, though feedback isn't the most pleasing. Actuation is even across the entirety of these. Button size and placement are good, as actuation is possible quite easily by rolling one's thumb across. A set of low-profile 2-pin switches from TTC (blue plunger) is used for these.

At the bottom of the mouse is a single button for switching between 2.4 GHz wireless and Bluetooth operation, which works in somewhat mysterious ways. If the PC is running, pressing the power button will shut the mouse "off" (i.e., it stops accepting any inputs), but an LED will keep blinking, which eventually stops. After it has stopped, moving the mouse will re-enable the LED, however. If the PC is not running, the LED won't be re-enabled when moving, so this is as close to "off" as it gets. In order to enable Bluetooth operation, the button needs to be pressed and held for five seconds. A seemingly unbranded tactile switch is used for this one.

Scroll Wheel

The scroll wheel is decent. Noise levels are high, especially when scrolling up, and tactility is merely average, with fairly distinct steps allowing for mostly controlled scrolling. The encoder comes from CF (ChangFeng, black) and has a height of 12 mm. Actuating the middle (scroll wheel) click requires medium to high force. A seemingly unbranded tactile switch is used here.

Surface

The M75 Air 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 M75 Air is easy. The screws, which are Torx T6, are found beneath the front and rear skates. After removing these, clips at the sides need to be dislodged, preferably by wedging a credit card or something similar in between. When doing so, make sure not to rip any cables when separating the top and bottom shell. The greater challenge lies in putting the mouse back together. I've found that this is can only be done by inserting the two screw posts at the front in a very specific manner, and ideally at the exact same time.

The internal design is very simple. The side buttons sit on their own PCB screwed to the top shell and connected to the main PCB through a ribbon cable. The battery is glued to the bottom of the side-button PCB. Everything else sits on the main PCB, which is fairly thin and affixed to the bottom with three screws. The MCU is a Nordic nRF52840, whose datasheet can be found here. In addition, a Macronix MX25U8035F, which is a serial NOR flash memory, and whose datasheet can be found here, is likewise located on the main PCB. Production date for the side-button PCB is the 28th week of 2023.


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