Truthfully, there isn't much to say about the M42 Wireless that hasn't already been said about the Xtrfy M4 Wireless. Still, some differences can be found, minor as they may be.

Much like the M4 Wireless, the M42 Wireless allows for hardware customization. As already possible on the wired M42, the default back cover can be swapped for one with a less pronounced hump curvature. This is achieved employing three screws, which is more stable but less convenient than the magnetically attached covers on the wired M42. Once again, Xtrfy provides the STP files necessary for 3D-printing a custom back cover, allowing one to go beyond the included ones. The ability to change the battery position also makes a return from the M4 Wireless. In practice, the difference is subtle at best, which is why I'm still inclined to consider this a gimmick. As a result of these additions, along with the addition of a 500 mAh battery, the M42 Wireless ends up weighing 9 g more than the wired M42, or 67 g in total. While in line with the competition from Glorious among others and certainly light enough, this weight is at the upper range of what I'd consider reasonable for a design that has holes literally everywhere: bottom, top, sides, and part of the main buttons. For comparison, the larger, and also hole-free Razer Viper V2 Pro manages to weigh 58 g, 9 g less. To compensate for the generous amount of holes, wall thickness on the M42 Wireless is above average, resulting in above average rigidity of the shell. My sample has minor creaking but no flexing, and actuating the side buttons by squeezing laterally is impossible. In short, build quality doesn't suffer from the Swiss cheese design, and any displeasure related to that may only be related to how it looks.

A benefit of the large battery is battery life. Xtrfy cites 75 hours, which seems believable without illumination. Charging is quite fast as well at 0.338 A on average, which, coupled with the flexible charging cable, allows one to minimize the time spent charging, all while being able to continue playing without feeling overly restricted. Wireless performance likewise is as strong as expected: Wireless motion delay sits at around 1 ms, general tracking is fine, CPI deviation nonexistent, and excluding polling rates below 1000 Hz in wireless, polling is stable throughout. Click latency is on the expected level considering the MCU used for the M42 Wireless, which is a CompX CX52850. At the 2 ms debounce time setting, click latency in wireless mode sits around 4.9 ms, which is low, but could be lower. To be exact, 1 ms lower, as the CX52850 allows lowering debounce time down to 1 ms (the 0 ms setting is functionally the same). To achieve parity with other CX52850 mice such as the Pulsar Xlite Wireless, Xtrfy may want to give users the option to lower debounce time to 1 ms, along with the ability to utilize the full granularity afforded by the MCU, which allows for adjustment in increments of 1 ms. This restriction aside, the M42 Wireless impresses with its degree of on-board configuration options. Almost everything one would expect from a software solution can be changed directly on the mouse, aside from CPI adjustment and button remapping, the latter of which is possible through third-party solutions.

When it comes to the buttons, Xtrfy once again opted for Kailh GM 8.0 switches for the main buttons. Button response is expectedly firm and satisfying, and the buttons themselves are rock solid too on my sample, with lateral play being virtually nonexistent. The side buttons are pleasing as well, with even actuation but slightly higher post-travel on the back button. The M42 Wireless utilizes a slightly different scroll wheel encoder than the M4 Wireless, which is largely identical in terms of tactility, but emits a slight grinding noise when scrolling up. This only was the case on the first sample I've tested, however, whereas the second sample didn't exhibit such an issue. Hence, it is entirely possible that this is little more than a one-off occurrence. The feet are differently shaped than the ones on the wired M42 or M4 Wireless, but identical in terms of glide properties, and thus just as excellent. As always, a set of replacement feet is included, which is most welcome. Of course, a wireless extender is also included, which I consider an essential addition these days.

Overall, the M42 Wireless suffers only from the smallest of issues, many of which are more nitpicking than actually worthy of genuine criticism. Compared to the performance wise near identical Pulsar Xlite Wireless V2, the M42 Wireless does cost $20 more, but given the level of quality, ability to adjust the shape to a degree, and the shape itself, which continues to be a rather unique design, the M42 Wireless is reasonably priced, and accordingly deserves our Editor's Choice.

As for the competition, there is no shortage whatsoever. The Razer Viper V2 Pro weighs less while having no holes, has great performance, much lower click latency owing to optical switches, similarly good buttons, but a resource-heavy software and hefty price tag of $149.99. For $89.99, the Fnatic BOLT has similarly great performance, the same weight despite no holes, and comparably good main buttons, but suffers from its poor software and lackluster side buttons. The $79.99 Glorious Model O- Wireless scores in the click latency, weight, buttons, and charging cable department, but wireless motion delay is below par, and the software is a resource hog. Lastly, the Fantech Helios XD3 V2 is the budget option for $59.95, with similarly great performance, very good buttons, and a big battery, but much higher weight, a stiffer charging cable, and lackluster side buttons.