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 and 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" and 5-1/2" as well as handy markers that measure 2x4 board dimensions of 1-1/2", 3" and 3-1/2".