Set a consistent seam allowance in seconds. This sturdy magnetic guide positions against a metal needle plate to hold fabric on track for straight, uniform seams—perfect for piecing, hemming and top-stitching. Slide to adjust for common widths like 1/4", 3/8" and 5/8". Remove before cleaning or when not in use. Note: follow your sewing machine manufacturer’s guidance regarding magnets near computerized machines.