The right-handed ergonomic Xlite shape has been a staple in Pulsar's lineup ever since they first entered the gaming mouse market back in 2020. Whereas the original Xlite could be described as a Zowie "EC1.5," given how it landed between the EC1 and EC2 in terms of size, new sizes had been introduced with the Xlite V3, where the Large size ("Size 3") was larger than the original Xlite, whereas the Medium size ("Size 2") was smaller than the original Xlite. With the F01, which is launched under the Feinmann sub-brand, Pulsar adds yet another size, one that could be called an Xlite "Size 1.5," as this one is smaller than the Medium, but not as small as the Small size ("Size 1").

In general, products released under the Feinmann label are supposed to be special in some way, be it in feature set, materials used, or otherwise. Being made of a magnesium alloy, the F01 certainly fits that criteria, and both the extravagant packaging and added accessories successfully create a premium impression. At 46 g, the F01 is a good 10 g lighter than the Xlite V3 Medium, which of course is slightly larger and utilizes a different design. Since magnesium is far more rigid than ABS plastic, the F01 can get away with incorporating large holes of various shapes and sizes across the entire top shell without compromising structural integrity. While there are no holes at the finger contact points at the sides and on the main buttons, those applying a full palm grip may find their metacarpophalangeal joints snugly fitting into some of the holes in the top shell, which could be irritating. This aside, the execution of the magnesium shell on the F01 is great: there is no flexing or creaking of the shell when applying lateral pressure, the side buttons cannot be actuated by pressing below them regardless of force, and the fitting between the magnesium top shell and plastic bottom shell is good. The only flaw is a minor rattle when shaking coming from an indeterminable location, but unless actively looking for it, this is completely negligible.

Much like the Xlite V3, the F01 utilizes optical switches for its main buttons, albeit of a different make. Instead of RAESHA switches, the F01 comes with Kailh GO, which are familiar from the Endgame Gear XM2we and OP1we. Whereas on those, the Kailh GO had garnered a reputation of being rather stiff yet somewhat mushy, they fare a decent bit better on the F01. Actuation is both lighter and snappier, which no doubt is helped by the rigidity imparted by the magnesium shell. In addition, lateral movement of the button pieces is low, and pre-travel qualifies as moderate to low, further adding to a good impression. For the side buttons, Pulsar has likewise opted for switches from Kailh, albeit surface-mounted ones. While these score with low pre and post-travel, feedback is high-pitched and far from pleasing, though the actuation point at least remains even across their entirety. The scroll wheel is well familiar from the Xlite V3, as once again a Pulsar-branded "Blue" encoder from F-Switch sees use. Noise levels are mostly under control on this one, and tactility is good, with clearly discernible steps allowing for controlled scrolling. No surprises are encountered in the feet department, either: much like on the Xlite V3, the feet are made of pure PTFE and glide well, though on the F01, an additional set of UHMWPE dot skates is also included, which tend to last longer than PTFE while providing similar glide properties.

Thus far, Pulsar largely resorted to firmware and software solutions from CompX, much like other competitors such as LAMZU, SCYROX, or Fantech. With the F01, Pulsar not only debuts their own custom sensor dubbed XS-1, but also their own in-house firmware. The XS-1 is based on the PAW3950, offering slightly higher maximum CPI and CPI adjustment in increments of 10. As far as click latency goes, Pulsar's efforts have been mostly successful. At 8000 Hz, the F01 averages no more than 0.5 ms, which is up there with the best, and 1000 Hz is only marginally worse at 0.7 ms. This only applies if debounce time has been set to 0 ms, though since optical switches are inherently incapable of developing unintended double-clicking due to wear and tear, and given that a slam-click prevention algorithm is present, there is no real reason not to use the 0 ms setting, as not doing so will only give one higher click latency. Unfortunately, said slam-click prevention algorithm is flawed in that the first click after lift-off will have the full latency added upon lift-off (to prevent such accidental clicks when resetting the mouse) applied to it even when the mouse is no longer lifted. Roughly 12 ms are added, which of course isn't exactly ideal for consistency.

In terms of sensor performance, serious issues emerge. This became immediately obvious when I started testing the F01, as I wanted to do a single medium-speed swipe to take a look at tracking. Yet, despite not going fast at all, the cursor no longer responded, and only after turning the mouse off and back on again did normal operation resume. Upon closer inspection, I've found that reports were often delayed by 60 ms or more, and when the cursor no longer responded, the report apparently was only delayed, possibly by several minutes. At this point, I was sure that the mouse was defective, but somehow, this behavior corrected itself, and the mouse started to function normally. Still, the fact that this is possible at all certainly does not inspire confidence. Even if we ignore this initial issue for a moment, it seems clear that the F01 struggles with handling high velocities in general. For instance, when moving the mouse at upwards of 4 m/s, all my normal CPI steps except for the highest would occasionally be set to 400, and the highest one was set to 2100 CPI. When doing swipes on the desktop, this is no problem, but consider doing a fast swipe like that in game, and only those using 400 CPI in the first place would find that funny. Another and rather curious issue is that the number of counts per report is capped at 2047 (+/-) or 12-bit. By parsing the HID report descriptor, I've been able to determine that this is not a restriction imposed by a 12-bit HID descriptor, but rather a seemingly arbitrary output constraint within the firmware. In practice, the sensor will not malfunction, but any motion exceeding this limit will be clipped, leading to negative acceleration. This issue somewhat alleviates itself at higher polling rates, as hitting that limit will be difficult even when using the maximum CPI of 32,000 CPI, but still—why have this sort of limitation to begin with?

As far as base sensor performance goes, the F01 is largely unimpressive. While the target interval is averaged for each polling rate, polling is unstable in general, with off-period polls and elevated variance abounding. In fact, at 2000 and 4000 Hz variance is high to where I wasn't even able to reliably measure motion delay, which is certainly telling. From what I can tell, motion delay is the same across all polling rates, and without MotionSync, the F01 is roughly on par with the Logitech G403 (control subject). This is worse than what the Xlite V3 with its 4K wireless dongle was able to muster, which came in at a 0.7 ms advantage over the G403 at 4000 Hz. In addition, fairly large off-period polls occur somewhat regularly at 8000 Hz on the F01, where the poll is missed by multiple intervals (3+ ms). The only saving grace is CPI deviation, of which there is none. In summary, the F01 performs clearly worse than the Xlite V3 did.

Pulsar has issued new software for the F01, which delivers similar functionality and looks as the previous version of Pulsar Fusion and remains both pleasantly bug-free and conservative on resources. Pulsar makes no claims in terms of battery life, but a battery life indicator is included in the software, which isn't particularly accurate or reliable, but enough to allow gauging expected battery life. At 8000 Hz, the indicator went down by roughly 25% for every three hours of continuous usage, so around 12 hours may conceivably be expected, which should translate to around 60 hours at 1000 Hz. Obviously, these numbers aren't anything to write home about, though this isn't too surprising given that only a 240 mAh battery is used. Still, on a 28% larger capacity, the Razer Viper V3 Pro is able to squeeze out 42% higher battery life, so this comparison isn't too favorable for the F01. Another issue presents itself when it comes to charging. The F01 comes with a charging dock, which is certainly convenient, but it is also slow, very slow in fact. At around 0.1 A, charging the F01 requires some patience, and simply plugging the mouse in is not an option, as the F01 lacks a USB port altogether, so the cable for the charging dock being nicely flexible doesn't provide much solace either. Accordingly, keeping the F01 charged at all times is paramount, lest one will be left hanging.

The F01 retails for $179.95, and for that kind of money, one would rightfully expect virtual perfection, yet the F01 doesn't deliver. Aside from click latency, performance isn't anything special, sensor issues abound, and the slow charging really tests one's patience. Luckily, most of the issues the F01 has could be fixed in a firmware update, and on the physical side of things, the F01 has plenty to offer, as build quality is great, the buttons well-tuned, and the weight low. At the same time, Pulsar's own Xlite V3 has the F01 squarely beaten in terms of performance, and often can be had for less than half the price, so even if most of the issues get fixed eventually, making a case for the F01 at $179.95 would be difficult. As such, I'd suggest Pulsar's other offerings over the F01.