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. Non-slip with black markings. Easy to read numbers and gridlines. 1in grid with 1/2in, 1/4in, and 1/8in increments.