The Featherweight Accurate Seam Square simplifies seam accuracy. Achieve a proper seam allowance fast and easy by lowering the tip of the needle through hole of the desired seam width then use the square to align the edge of the Featherweight Accurate Seam Guide (sold separately). Fasten the seam guide in place and your seam allowance guide is set. Raise machine needle and be ready to sew! Accurate Seam Square is black and features the gold trim to emulate the vintage black Featherweights. Keep gauge handy whenever you want to set the ideal quarter inch seam allowance. Some quilters prefer a true quarter inch whereas others prefer a scant.