This 300mm Best Buy combination square is a multi-purpose tool, allowing you to accurately measure and level edges and corners. It can function as a framing square, tri-square, straight edge, level, depth gauge, layout tool, and has many more uses. How easy is it to use? The die-cast aluminium alloy handle has a sharp marking gauge and features clear ruler markings, as well as an easy-to-read level conveniently built into the handle. The grooved aluminium alloy blade has an adjustable thumbscrew.