Olfa Frosted Acrylic Ruler 6.5"x 6.5" Square- Great for squaring up the corners of blocks as well as accurate marking and cutting of patchwork or miniature quilts. This acrylic ruler is non-slip and is marked with black numbers and lines for clarity, your measurements will be clear and easy to read on light and dark fabrics. Has easy to read grid lines; 1" grid with .5", .25" and .12" increments for precise measurements. For right or left-handed use.