For the past decade, Logitech's MX Master line has been the best-of-the-best for productivity-focused mice. Each iteration has improved on the last and brought something new to the table, while still maintaining the core functionality that made the mouse special. The latest iteration—the MX Master 4—has big shoes to fill. The MX Master 2S got me through college, and I gifted my mom the 3S for Christmas on release. These mice have been a staple in my workflow (same for a few other WIRED staffers) since the original's debut. Like its predecessors, the MX Master 4 ($120) has an ergonomically sculpted shape, multiple thumb buttons, vertical and horizontal scroll wheels, and a litany of gesture-based controls. Alongside small improvements to its shape and materials, Logitech's newest mouse introduces haptic feedback and significantly expands gesture controls. Comfort and Usability Photograph: Henri Robbins The MX Master 4 retains the general shape of its predecessors. It is a fairly large right-handed mouse with two standard mouse buttons on top, a clickable scroll wheel, and a third button behind it to adjust the scroll wheel's mode from smooth to ratcheted scrolling. On the side, there’s a large rubberized thumb rest with one embedded button, three standard buttons in a line, and a horizontal scroll wheel above them. On the underside, there’s an on-off switch and a button to cycle through connected devices. The mouse is designed for a relaxed grip, allowing you to rest your palm comfortably across the body. There’s a peak between the index finger and thumb that houses the horizontal scroll wheel, and a comfortable indent for your thumb to rest on. The graphite-colored model's main shell is ABS plastic, with a transparent polycarbonate-like material on the mouse buttons, and a rubberized grip on either side of the mouse. The transparent buttons have a smooth, matte texture that allows for easy grip without being abrasive, but the surface picked up a couple of scratches during testing. The main body of the mouse is slightly textured, with a subtle knurling pattern embedded into the plastic. It isn’t noticeable at a distance, but it causes light that hits the mouse to create an interesting stippled effect.