With anything novel, teething troubles usually are both expected and to some degree excusable. The original Zephyr was no exception in this regard: While its built-in fan succeeded in keeping one's hands cool, it did so at the cost of a decent amount of electrical noise and vibration. The Zephyr Pro improves on its predecessor with a much more mature implementation. Equipped with a 30 mm fan instead of a 25 mm one, the Zephyr Pro is similarly effective when it comes to cooling, but cuts down on electrical noise in particular, and the fan runs much quieter in general. Some vibration is still present, but since the fan runs at a much lower RPM, major progress has been made in this regard as well.

Whereas the improvements in terms of fan performance are tangible, there is still a question mark behind the durability. The fan in the original Zephyr only had a sleeve bearing, and coupled with the fact that it wasn't mounted vertically, but rather at an angle, and warranty only lasting six months, the situation sure wasn't optimal. On the Zephyr Pro, Marsback doubles down on the mounting angle in that the fan is mounted horizontally, which is the worst possible scenario if a sleeve bearing is used. I've been told by Marsback that the Zephyr Pro is using a sliding bearing, which is commonly equated to a sleeve bearing, so there is reason to believe that the fan may not last particularly long. For what it's worth, Marsback at least gives a 1-year warranty on the Zephyr Pro, which provides some reassurance.

Aside from the fan, the original Zephyr also had a fairly unique shape. In fact, I've yet to see this shape realized on any other mouse, which is somewhat rare these days. The Zephyr Pro, on the other hand, comes with an entirely different and, dare I say, more generic shape. Essentially, it is a Glorious Model O with a Logitech G Pro Wireless hump, which isn't bad at all, but not quite as exciting. In addition to that, the Zephyr Pro has holes all over its shell, but in this case, they at least serve a practical reason in that they allow for airflow on top of the weight reduction. At 74 g, the Zephyr Pro is decently light, basically weighing the same a Model O would with an added fan. As far as quality goes, I haven't encountered any issues on my copy. Activating the side buttons by squeezing the sides is impossible, there is only minimal creaking, and no rattling unless the mouse is violently shaken. Both the main and side buttons provide a firm and snappy click response, and even though the scroll wheel is somewhat noisy, tactility is quite decent. A step back can be reported as far as mouse feet go: The original Zephyr came with non-dyed pure PTFE feet of excellent quality, whereas the Zephyr Pro merely features regular black-dyed PTFE feet. They're not bad, but certainly not as good as those found on the Zephyr.

When it comes to performance, the Zephyr Pro does some interesting things. Upon opening the software, one immediately notices the "Key Response" slider, which is set to 20 ms by default. Contrary to what this may have one believe, 20 ms actually means 2 ms, as shown in my testing. If desired, this value can be lowered all the way down to 1 ms, which results in a stunningly low click latency of around 0.1 ms (Ikari scaling). While the mouse does slam-click (i.e., accidental clicks when slamming down the mouse) at that value, having the ability to freely adjust click latency to such a low value already is commendable in itself. Speaking of the software, it has all the necessary features, no bugs, and is lightweight, in one word: perfect. As far as sensor performance goes, the Zephyr Pro does well with two exceptions. First, I've measured a flat base motion delay of roughly 1 ms, which isn't much but still unneeded considering other PMW3389 implementations don't have it. Second, polling stability suffers if select RGB lighting effects are chosen. Those valuing flawless polling stability may want to avoid those effects, which certainly limits the appeal of the otherwise rich RGB lighting on the Zephyr Pro.

All in all, I don't have much too complain about this time around. In fact, the Zephyr Pro doesn't miss an Editor's Choice by much and gets a well-earned Recommended award instead, along with our Innovation award for its fan implementation. If there ever is a third iteration of the Zephyr, I'd most welcome seeing a ball or fluid bearing used for the fan, along with a flawless sensor implementation. Still, even a year after the release of the original Zephyr, it and the Zephyr Pro continue to be the only mice that combine a working fan implementation with high-grade internals, which puts them in a unique position. Despite that, the Zephyr Pro is priced more reasonably than the no longer available Zephyr was, although at this point in time, I'm not entirely sure what the MSRP even is. Still, no matter if it's $69, $59, or $49, the Zephyr Pro is a compelling option, especially for those with sweaty hands or suffering from hyperhidrosis. Furthermore, Marsback has provided a $10 discount code for TechPowerUp readers at checkout: TPUONLY. Please note that this isn't an affiliate link or referral code, and TechPowerUp does not receive any kickbacks.