OLFA 1071797 QR-4S 4-1/2-Inch Square Frosted Advantage Acrylic Ruler Designed for right and left-handed users Excellent for trimming half square triangles and small paper-piecing Special marked grid lines for accuracy and precision Frosted backing allows for easy reading on dark, light or patterned materials Non-slip features are manufactured into the ruler and will not wear off over time