Compare the actual dimensions

The Razer Gigantus V2 review in How To Geek illustrates how dramatically a large desk mat can affect a setup. The reviewed 3XL version measures about 47.24 by 21.65 inches, while the cited XXL option is roughly 37 by 16 inches. These dimensions describe different footprints, not just different labels on otherwise interchangeable accessories. Check the exact model size against the usable part of your own desktop.

Allow for stands and accessories

The reviewer describes repositioning desk accessories and encountering a monitor stand that interfered with the mat. Rather than relying on a product photograph, the article recommends cutting cardboard to the intended size before purchase. Place that template where the pad would sit and inspect the remaining room around the monitor, speakers and other tools. The review also notes a cloth surface and rubberized base, but the practical sizing lesson is broader: a mat can cover almost an entire desk without fitting comfortably around everything already on it.

Check an Oversized Desk Mat With a Cardboard Template
The Razer Gigantus V2 review in How To Geek illustrates how dramatically a large desk mat can affect a setup.