To develop one of the world's best rafter squares, Johnson first had to engineer the "EZ-Read" finish, its revolutionary anti-glare protective coating that diffracts sunlight rather than reflecting it, so it looks as crisp in full sun as it does in the shade. The "EZ-Read" finish also increases friction to better secure your square against your lumber when using it as a saw guide. The "Johnny Square" is highly durable & accurate. Its solid aluminum body construction with CNC machined edges ensure an accurate reading every time. This rafter square also features continuous scribing notches that are ideal for ripping at 3-1/2" & 5-1/2" as well as handy markers that measure 2x4 board dimensions of 1-1/2", 3" & 3-1/2".