By default, G-Wolves mice already are primarily intended for enthusiasts. The HSK Pro 4K is different in that it appeals to a niche within a niche: Users of fingertip grip, who also don't mind paying almost $180 to get something tailored to their needs. While mice primarily conceived for palm or claw grip are a dime a dozen, dedicated fingertip grip continue to be a very rare commodity. The Xtrfy MZ1 still incorporates the palm and therefore doesn't qualify as a full fingertip grip mouse, which only leaves the Zaunkoenig M1K and M2K, which can be operated with nothing but one's fingers and are even pricier. In fact, compared to the now discontinued 300€ ($330) M2K, the HSK Pro almost comes across as a bargain, as it costs half as much while being wireless, and being almost a match in terms of weight and latency.

For a fingertip grip mouse, the entire rear part of the mouse, which otherwise would provide palm support, is entirely superfluous. Hence, the HSK Pro 4K is reduced to litte more than the main buttons and scroll wheel, and the only reason the rear hump exists are the side buttons, which can sit higher that way. Compared to the M2K, the HSK Pro 4K is even smaller and most importantly narrower, which can make the transition from a regular mouse more difficult. Hence, those with larger or wider hands may struggle using the HSK Pro 4K, especially since the room for one's thumb is quite limited still, occasionally resulting in one hitting the side button unintentionally. Still, after some getting used to, I found myself surprised how organic using the HSK Pro felt, despite never using fingertip grip otherwise.

As a result of its small size, the HSK Pro 4K is exceptionally lightweight at 26 g, which is doubly important given that the mouse is controlled only by one's fingers, which typically aren't as strong as the entire hand. The bottom is largely open, holes for weight reduction are only used on parts that aren't contact points, and the build is surprisingly solid. When applying pressure, there is no creaking or flexing at all on my sample, actuating the side buttons by pressing below them is impossible, and shaking reveals just a minor rattle coming from the main buttons, which isn't noticeable during actual use. The main buttons do have some noticeable pre-travel, but the Zippy switches used on other G-Wolves releases such as the Hati-S Plus 4K or HTX 4K afford a firm and snappy button response nonetheless. A TTC yellow (or "gold") encoder sees use as well, which provides very nice tactility when scrolling, albeit at elevated noise levels due to the open bottom. For the side buttons, G-Wolves has opted for low-profile switches from Huano, which score with impressively low pre and post-travel, coupled with even actuation. Much like on other G-Wolves releases, the bottom has no recesses for the mouse feet, allowing one to install skates of virtually any size or shape, several sets of which are included with the mouse, and the default one glides very well.

In terms of performance, the HSK Pro 4K is on the same excellent level as other G-Wolves releases such as the Hati-S Plus 4K and HTX 4K. There is no CPI deviation at all, general tracking is fine, and polling stable throughout, save for a select few bouts of instability, which I'm unable to reproduce consistently and which very well may be host-related. Much like recent Razer releases such as the Viper V2 Pro in conjunction with the HyperPolling Wireless Dongle, the HSK Pro 4K is capable of true 4000 Hz wireless polling, which results in exceptionally low latency. Click latency in 4000 Hz wireless operation sits at just 0.6 ms when using the lowest debounce time value, and is barely any higher at 0.8 ms when using 1000 Hz. Likewise, motion delay at 4000 Hz is 0.5 ms lower than on the Logitech G403 (control subject), and identical when using 1000 Hz. These values are without MotionSync, which improves tracking consistency by synchronizing SPI reads with USB polling events, but does increase motion delay by roughly 0.5 ms at 1000 Hz. The only issue related to performance I could find is a tracking error which is introduced at and above 9000 CPI, where smoothing is first applied. This has already been the case on the HTX 4K, and outside of simply avoiding the higher CPI range, which is recommended due to higher motion delay by virtue of smoothing anyway, there isn't much one can do about it. In addition, 2000 Hz likewise appears to be bugged, which had been the case on both the Hati-S Plus 4K and HTX 4K before. A rather curious yet still noteworthy detail is that onset motion delay is less pronounced on the HSK Pro 4K compared to the Hati-S Plus ACE/4K or HTX 4K, as the framerate ramps up more rapidly when moving from a standstill.

Given that keeping the weight as low as possible is paramount for the HSK Pro 4K, the battery installed by default only has a capacity of 130 mAh. Relatively speaking, charging is very sluggish at little more than 0.1 A, but is, due to the low capacity, decently fast in absolute terms. Unfortunately, the charging cable still isn't particularly flexible, which becomes particularly noticeable on a mouse this small and light, which is why playing while charging isn't really an option. Unlike on the Hati-S Plus, the on/off-switch can be accessed just with one's fingers, though not as easily as on the HTX 4K. Since the software includes a reasonably accurate and reliable battery charge indicator, I can give a rough estimate of battery life: I'd expect battery life to be around 10 hours at 4000 Hz and around 40 hours at 1000 Hz. For those who find these numbers too low, G-Wolves has included a 300 mAh battery, which will easily double battery life. Speaking of the software, this one still is among the most pleasant to use mouse softwares, as it doesn't require installation, and resource usage is kept under control. This is particularly relevant in that the HSK Pro 4K lacks a dedicated CPI button, which is why one will have to resort to the software for changing the current CPI level.

The HSK Pro 4K isn't for everyone, and that is reflected in the price. At $179.00, the HSK Pro 4K goes for another $10 more than the already pricey HTX 4K. At the same time, special interest products always come at a premium, and there is no denying that in terms of performance and build, the HSK Pro 4K is a fine piece of hardware. Moreover, for those exclusively infatuated with fingertip grip, there really aren't that many alternatives, and even fewer that are substantially more affordable. Accordingly, the HSK Pro 4K earns our Recommended award. When buying directly from G-Wolves in particular, do keep in mind that customer service may be lacking to nonexistent.