A razor knife can slip over a flat ruler and give you a nasty cut. The new Safety Ruler has a curved aluminum guard that prevents the razor from accidentally slicing your fingers. On the back side is a non-slip blue rubber gripper material that locks he ruler down. Unique transparent sliding marker moves along the scales. If you have to cut a batch of 24 inch signs, set the market at 24 mark and cut. Very fast, accurate and easy to use. The extra wide 2.6 inch ruler gives you a generous 2 inch comforts grip and your hand fits sweet inside the gently curved finger guard.