The typical MMO mouse is a big, hefty thing. It’s not a genre that tends to demand such sites and precision that a few extra grams of mouse weight can make a difference, and when the design goal is “as many buttons we can possibly fit”, things get large. But with the Aerox 9 Wireless, SteelSeries set out to make the lightest wireless MMO mouse in the world—an experiment that, for the most part, his the mark.
Weighing in at just 89g, it sure hits that “lightweight” mark. It’s only slightly heavier than Razer’s wired Naga X, despite the extra heft of an internal battery, and far lighter than any other wireless option with the 12-button MMO side panel. And while that feathery movement isn’t necessarily going to give you the competitive edge in an MMO as it might in an FPS, in terms of comfort and hand fatigue during marathon play sessions, the lighter touch goes a long way. (It does also make it a versatile option fit for folks who play a range of games, though a multi-genre mouse like the Aerox 5 or Rival 5 might be a better option there).
That ultra-light finish doesn’t come at the expense of build quality, either. The honeycomb shell won’t appeal to everyone, but it certainly does the job if shaving off a few grams while keeping the mouse feeling solid. The buttons, feet, and USB-C connection for charging all feel sturdy, even after a few weeks of giving the mouse a good thrashing. The internals, too, look firmly built from what I can see through the mesh and show no signs of destabilising even after some pretty aggressive use. I have some concerns about dust build-up over the long term, but IP54-rated dust and liquid protection mean that should, hopefully, be nothing that a quick vacuum can’t resolve.

The Aerox 9 is every bit as responsive as you’d hope, with a sensor that tracks smoothly over most mouse-ready surfaces. From a SteelSeries Qck EDGE mouse mat, to a bare desktop, to the arms of a leather couch—even the side of my leg, when laptop gaming in maximum comfort mode—the mouse movements are quick, precise, and accurate. Battery life is impressive—I’ve been using it heavily for three weeks, and drained the battery exactly once—and it recharges rapidly, with a lengthy charge cable so you can still use it in a wired form while charging.
It supports both Bluetooth and 2.4G wireless connections, and the ability to jump between different modes at the flick of a switch is handy if you use the mouse across multiple devices without having to move the dongle each time, though it’s worth keeping in mind that Bluetooth only supports the default button settings. The dongle is USB-C, which is fine and expected, though if you’re using a device without a USB-C port the packed-in adapter situation is kind of awkward: the dongle, plugged into an adapter with two USB-C ports, plugged into the 2-metre charging cable. It works, and it’s nothing a cheap USB-A to USB-C adapter couldn’t resolve, but it’s odd to not just have such an adapter included.
Button layout is arguably what matters most in an MMO mouse, and the Aerox 9 Wireless mostly hits the mark there—though some of the compromises to get the weight down do also show through. The form factor is similar to the Rival 5, ensuring a comfortable grip and easy access to the main buttons, but with a 12-button side panel in the common 3×4 grid layout. The buttons themselves are light and easy enough to press, but not so twitchy that you can’t rest your thumb there without accidentally hitting something. With the help of a raised bump on button 5 and the ergonomic design of the grid, the buttons are all quickly and easily distinguishable on the fly—there’s no worry about getting lost and pressing the wrong thing.

The one concern is size: basically, it’s a smaller-than-usual MMO mouse with smaller-than-usual side buttons, which can make cleanly pressing individual buttons a bit tricky. I don’t think I have massive thumbs (though I could be mistaken), but I still occasionally find myself accidentally getting a stray extra button if I get twitchy or careless, especially with the middle row. That’s never ideal, and while it can be mitigated to some extent with clever mapping, the better option would just be to have buttons that are big enough to not have this issue.
That’s part of the reason I don’t recommend using the default button mapping (sorry, Bluetooth convenience): if you’ve got your whole regular 1-to-12 hotbar on the side panel, with all your standard attacks and spells and whatnot, you’ll run into problems. Thankfully, the SteelSeries Engine software makes custom button settings both extensive and easy to set up. There’s a full suite of keyboard inputs, OS shortcuts, mouse buttons, and media controls available for each button, and recording macros is quick and painless. Most helpfully, you can set custom profiles for different applications, that take effect automatically when that software is running—even if it’s already running. That means you can have Engine and whatever game you’re setting up running concurrently, flicking back and forth between the two to tweak settings, try things out, and match mouse settings to the in-game keybinds.
And that’s how I wound up with a rather weird but extremely handy (for me) Final Fantasy XIV setup: 1, 2, and 3 set to my three most important quick-reaction buttons (interrupts, instant heals, etc), a panel of less frequently used cooldowns on 7 to 12, 4 and 6 as more convenient CTRL and Shift modifiers, and 5 as a jump button—because you have to have jump on the mouse if you want full mobility with just your mouse hand. Hey: if it works, it works.

Overall, the Aerox 9 Wireless is an impressive mouse, and a largely successful experiment in going ultra-light with an MMO mouse. MMOs may not demand the degree of precision that FPSes do, but reduced weight goes a long way in terms of comfort, especially in longer play sessions. The reduced size compared to more hefty alternatives can make the side panel buttons a little awkward for folks with bigger thumbs, but by and large, the design works well, giving quick access to a wide array of in-game actions, with SteelSeries’ usual wealth of customisation options. If you’re after a light, comfortable MMO mouse, you could do a lot worse than the Aerox 9 Wireless.

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