The Kapro 447 Mason Square with 3 masonry specific scales: standard masonry rule (standard spacing) , modular masonry rule (layout of commercial masonry) and oversized masonry rule (oversized spacing) Ideal for beginning the laying out at the base of the wall and tough to reach locations. Keeps handy residential and commercial masonry formulas at your fingertips with conversion charts on both sides of the square. Its anodized profile resists wear and corrosion caused by dirt and mud like standard rulers. Other features include: scribe indicators at 1/4in increments, a pivot point to layout rake (angles) , and a 90 layout for hypotenuse for finding plumb easily. In addition, its size is ideal for marking CMU and all masonry cuts. This means you can use to cut on full 8in masonry blocks.