With 1⁄8″ mini grid and extra 1⁄2″ for seam allowances on two sides. Great for scrapbooking, foundation piecing and cutting and squaring blocks up to 41⁄2″. Made of strong and durable premium quality acrylic plastic. Unique black and yellow double sight lines for easy viewing when working with light and dark fabrics. Laser cut to within 0.002″ accuracy with a smooth finish. Specially designed for right and left handed use.