The Magnetic Seam Guide attaches to the metal throat plate on a sewing machine. It's ideal for ensuring uniform seam width and as a guide to straight stitching. The anti-skid design prevents the magnet from sliding around. Lightweight rust-free construction compared to a traditional metal body. The cheerful smiley face design is available in Aqua Blue, Jet Black, Hot Pink and Orchid Purple. Presented in a countertop magnetic display board. Not recommended for computerized sewing machines.