The center is now precut to give you a smooth surface for sewing. Lori Holt designed her Seams Sew Easy™ Seam Guide for an accurate 1/4in seam and for constructing easy corner triangles. This tool saves time by not having to mark lines on your fabric when sewing half-square triangles, flying geese or snowballs. The center circle of the guide is also marked with 1/2in grid lines for a wider seam allowance. This is a seam guide that temporarily adheres to the bed of any sewing machine. These grid lines also help to ensure correct placement when adhering to your sewing machine bed.