No matter how good an eye you have for lining up paper or fabric, you need a ruler for precision "” and not just any ruler. You need a square ruler, like this OLFA® ruler, for accuracy. Use it to square up corners of blocks, for marking and cutting patchwork and miniature quilts or photos and mats. Good For: precise measurements and cutting angles for sewing and quilting. Frosted acrylic surface allows black imprinted numbers to be read effortlessly. Frosted surface is non-slip for extra stability and safety when cutting. Designed for accuracy and precision with grid lines marked in a 1/8", 1/4", 1/2" and 1" increments.