Smiley Seam Guide - Magnetic Magnetic straight edge to keep your sewing straight £2.50 inc. VAT Quantity: at £2.50 each Add To Basket 9 in stock. Magnetic seam guide attaches to metal throat plate on sewing machine. Ideal for ensuring uniform seam width and as a guide to straight stitching. Anti-skid design. Not Recommended for computerised sewing machine.