If you’ve shopped around for a wireless mouse at any point in the past decade, you’ve probably seen lots of people recommending a Logitech MX Master. There’s good reason for that: They aren’t cheap, but they’re usually comfortable, versatile and loaded with features designed to make working in front of a monitor all day a little less annoying. The current MX Master 3S has sat at the top of our own wireless mouse buying guide for some time now. Now, three years after releasing the 3S, Logitech is rolling out the new MX Master 4, which costs $120 and will ship in October. I’ve been able to test it out for the past few weeks. For the most part, this is an iterative update, with the same general shape, battery life, 8K DPI sensor and ultra-quiet clicks as the MX Master 3S before it. It is a touch heavier (150 grams vs. 141g), wider (3.48 inches vs 3.32 in.) and taller (5.05 inches vs. 4.92 in.) than the last model, but if you found the 3S or older MX Master 3 comfortable, you should have few issues here. That said, it’s still a hefty mouse designed for palm grippers and right-handed users: Its gentle contours, generous hump, ample thumb rest and large buttons will fit like a glove if that describes you, but lefties and those with especially petite hands won’t agree. Jeff Dunn for Engadget The flashiest change here is the addition of haptic feedback, which is built into a small panel within the mouse’s thumb rest. You can customize the intensity of this effect through Logitech’s Options+ software — or turn it off entirely — but it essentially brings a modicum of smartphone-style feedback to your desktop. When you first pair the mouse, for one, you’ll feel a little bump. The same goes if you move between devices using Logitech’s “Flow” feature. When battery is low, it’ll vibrate. If you’re trying to precisely line up a graphic in an app like Photoshop, you’ll get a little buzz when you’ve moved it to the exact right spot. Advertisement Advertisement You’ll also feel it when you hover over options in the Actions Ring, a customizable overlay that presents different shortcuts depending on the app you’re using. This pops up when you click the side panel; you could use it quickly access the screenshot tool while in Chrome, for instance, or the brightness and contrast sliders in Photoshop. If all of this sounds like a gimmick, well, yeah it kind of is. It’s not the kind of thing anyone needs. But the effect is surprisingly subtle on the default “medium” setting, and there’s a level of reassurance that comes with feeling a confirmed action instead of just seeing it. I found it more pleasant than distracting. The catch is that only a few apps will natively support the MX Master 4’s haptics at launch: Photoshop, Lightroom and Zoom, with Adobe Premiere Pro to follow soon after. You’ll still be able to utilize the haptic feedback on a system level on Windows and macOS, and Logitech is releasing an SDK for more developers to integrate the functionality, but we’ll have to see how many do so. Customizing the Actions Ring in Logitech's Options+ app. (Logitech/Jeff Dunn for Engadget) Another change is with the mouse’s coating, which trades the 3S’ rubbery finish for a lightly textured plastic around the top. (The thumb rest and right side still use rubber.) Some users have complained about older MX Master mice peeling and wearing down after extended use; time will tell how well the new model holds up, but it should avoid the same sort of sweat-induced degradation. Either way, I’ve found it smooth to the touch without being slippery. I also haven’t been able to replicate the accuracy issues some 3S buyers have had with that mouse’s electromagnetic scroll wheel, which is still made of a high-quality metal and lets you conveniently swap between a notched and free-spin scroll on the fly. There are other minor tweaks and improvements. The receiver included with the Windows model is now USB-C instead of USB-A. The horizontal scroll wheel on the side — which remains a blessing for navigating spreadsheets — extends a little farther with each spin. The PTFE feet on the bottom are a bit larger for a smoother glide. The dedicated gesture button is no longer awkwardly integrated into the thumb rest; instead, it’s been pulled out ahead of the two programmable side buttons. Logitech says there’s a more powerful chip inside the mouse to improve connection quality. The edges around the main click buttons are now translucent: nothing major, but a bit more stylish. The screws on the bottom are now exposed, too, which Logitech says should be helpful for recycling purposes down the road. Logitech The rest is largely the same as before, which isn’t a bad thing. The best feature here is still the virtually silent main buttons, which keep a pleasing level of travel but will never bother anyone around you. Battery life is still rated at a solid 70 days, which seems about right — I haven’t charged the mouse in about a month and the Options+ app says I still have about 50 percent juice left. The design still feels super sturdy, with no flexing or creaking. The side buttons feel firm and tactile. Options+ is resource-heavy but still intuitive enough for reprogramming buttons and customizing app-specific settings. It can still track on a variety of surfaces, including glass or the fabric of my couch. You can still connect to three devices simultaneously and switch between them with a button on the bottom, too. Advertisement Advertisement On the downside, there’s no USB-C cable included in the box anymore, and the polling rate is still set at a basic 125Hz, which means tracking isn’t quite as buttery smooth as it could be. The Mac version doesn’t come with a USB receiver, and there’s still no built-in storage compartment for the dongle with either model. You also need to keep Options+ open to feel the haptic feedback, which is annoying. Some of those complaints have been issues for a while, so it’s frustrating to see them three years later. Still, they’re probably not dealbreakers. The MX Master 4 may not be a essential upgrade if you’re happy with an older MX Master mouse, and if those didn’t work for you before, this one probably won’t work for you now. But if you’re a power user in the market for a new productivity mouse, we’d expect this newest iteration to be as popular as its predecessors.