The Hati-S remains among G-Wolves's most popular shapes, and in recent times we've seen releases of the larger Hati-S Plus and shorter Hati-S. The Hati-S Ultra 8K, then, finally brings the original Hati-S back to the present. Now at 31 g, the Hati-S Ultra 8K is even lighter than the smaller Hati-S2 8K at 34 g, although at a certain cost. Whereas the Hati-S2 8K had an open bottom and solid top shell, the Hati-S Ultra 8K does utilize holes rather generously. Both the back and large portions of the main buttons are punctured, leaving only the sides and supposed finger contact points on the main buttons solid. Build quality, at least, is still effectively flawless on my copy: there is no rattle when shaking, minor creaking but no flexing of the shell when applying lateral pressure, and actuating the side buttons by pressing below them cannot be done, regardless of force. As with previous G-Wolves releases, the PCB has been extended such that it supports the shell, whose walls otherwise would be too thin. A most effective design approach, evidenced by the fact that when accounting for size, the Hati-S Ultra 8K matches if not surpasses the HTX Mini 8K at 28 g.

As far as switches go, the Hati-S Ultra 8K essentially matches the Hati-S2 8K. The main button switches come from Huano and are of the blue transparent shell, pink plunger variety. Compared to the Hati-S2 8K, these are implemented in a much nicer fashion on the Hati-S Ultra 8K. Pre-travel is moderate, but post-travel very low, and button response as a whole is firm and snappy. Some lateral movement can be provoked still, although it remains unnoticeable during actual use. The side buttons are outfitted with 2-pin, low-profile TTC switches of the brown shell, blue plunger variant. On the forward button, pre- and post-travel are low, but the back button has moderate pre-travel and, more importantly, significant post-travel, to where the button can be pushed into the shell almost in its entirety. For the scroll wheel, G-Wolves once again has opted for the TTC blue/yellow core encoder. Tactility is great on this one, as each step is clearly defined, but scrolling up is unusually noisy. I'm inclined to ascribe this to unit-to-unit variation rather than the specific encoder size (12 mm), but ultimately, I would expect this to be the case on all copies. Much like on previous G-Wolves releases, the bottom lacks indents for feet, allowing one to apply feet of non-default sizes and shapes. Aside from the dot feet installed by default, two sets of larger feet are included with the mouse, along with three sets of dots. They're all made of pure PTFE, and glide very well. Of note is that the Hati-S Ultra 8K lacks a sensor ring entirely, which isn't necessarily an issue, but having one would probably be better for users of soft mats in particular.

With the Hati-S Ultra 8K, G-Wolves finally adopts PixArt's latest PAW3950 sensor, along with the familiar Nordic nRF52840 MCU. Testing has been performed on the 01.00.37 firmware, which performs slightly differently compared to previous versions. CPI deviation sits at a rather easily corrected +3.8%, matching the Hati-S2 8K. General tracking shows no issues, irrespective of whether MotionSync is enabled. Polling presents a somewhat mixed picture. At and below 1000 Hz, polling is generally stable, although occasionally, longer sequences of off-period polls show up. Above 1000 Hz, polling is stable, except for 4000 Hz, which too shows these bursts of off-period polls, which increase motion delay variance. Unlike with the PixArt 3395, which had trouble maintaining the target interval of 125 us with MotionSync enabled at 8000 Hz, the newer 3950 has no such issues, delivering a flawless 125 us interval. Speaking of motion delay, both 2000 and 8000 Hz post a lead of 0.5 ms over the Logitech G403 (control subject), whereas 4000 Hz falls a bit behind. Compared to the older 00.00.17, these numbers aren't as stellar, though battery life benefits from the newer firmware. Click latency too is higher compared to firmware version 01.00.36 and earlier, as the slam-click filter has been fixed, such that the full ~16 ms defer-type debounce delay is no longer applied to the first click after lift off. At 0.4 ms on the lowest debounce time setting, the Hati-S Ultra 8K remains plenty fast, however, and this applies regardless of polling rate—hence, even when gaming at 500 Hz, one gets to enjoy 8000 Hz-level click latency.

G-Wolves cites up to 80 hours of battery life at 1000 Hz, but even though the web driver includes a percentage-based (increments of 5%) battery life indicator, it proved unhelpful during the review, as it didn't budge one bit. Still, given the battery capacity of 250 mAh, it is reasonable to assume that the Hati-S Ultra 8K indeed sits somewhere in the 70–80 hours range at 1000 Hz, and accordingly less at higher polling rates. Charging isn't all that speedy on the Hati-S Ultra 8K, but decent enough, though playing while charging won't be an option with the included cables anyway. The first one isn't all that flexible to begin with, but more importantly seriously short at 1.25 m, whereas the second one is a bit longer at 1.45 m yet even stiffer. As such, it is best to keep the Hati-S Ultra 8K charged at all times to minimize forced downtime.

As with other recent G-Wolves releases, configuration on the Hati-S Ultra 8K is done through a web driver. Due to using WebHID, this will only work in Chromium-based browsers such as Chromium or Edge. Hence, for those not already using these browsers, being directed towards a web driver requires installing an additional browser, which of course comes with its own resource footprint, much like standalone peripheral software would. In addition, if G-Wolves were to go defunct, or decide to no longer host the web driver, configuration would become impossible, as a local copy unfortunately won't work. This is doubly problematic in that the HTX Mini 8K doesn't even have a CPI button, so even something basic as changing CPI requires using software. As such, I consider the web driver a step back compared to the previous standalone application featured with earlier G-Wolves mice, and would welcome if G-Wolves would also release a desktop version of their web driver in the future. As for the driver itself, I couldn't find any bugs, and all the relevant options are present. The only minor issue is that setting changes can still be made after the mouse has entered sleep mode, yet won't be applied, which isn't communicated through the UI. An additional oddity is that any adjustment to the debounce settings will only take effect after the mouse has been lifted and reset once. Compared to earlier 3395 releases, two new settings exclusive to the 3950 are available on the Hati-S Ultra 8K: lift-off distance may be set to 0.7 mm, and the sensor angle can be adjusted from -30° to 30° in increments of 1°.

The Hati-S Ultra 8K is offered in two different editions. The deluxe edition depicted in this review goes for $149.00, whereas the standard edition weighing a couple of grams more and limited to the black colorway, is sold at $119.00. Obviously, part of the selling proposition of the Hati-S Ultra 8K is the weight, which is why that weight increase may be considered particularly undesirable, but in practice, ~3 g on top will be hardly felt. As such, I consider the standard edition the better buy, and it compares favorably to both the Hati-S2 8K ($139.00) and HTX Mini 8K ($159.00). When comparing the Hati-S2 8K and Hati-S Ultra 8K, the former may appeal more to those favoring a more aggressive claw grip, as it is shorter than the Hati-S Ultra 8K, and the solid shell is both functionally and aesthetically more pleasing. At the same time, a more relaxed claw grip and larger hands in general align better with the Hati-S Ultra 8K. In summary, the Hati-S Ultra 8K earns our Recommended award.