The "Featherweight Accurate Seam Guide" fits the Singer Featherweight 221, 222, as well as most all other vintage Singer models (i.e. 15, 66, 99, 127, 128, 185, 201, 301, 319, 401, 500, etc.) Each guide 3/16" thickness, and the acrylic helps keep the bed of the machine protected from scratches. Featuring the darling gold decals on a clear surface to match the classic Featherweight design. Includes screw and washer for seam guide stability and consistent, accurate seams (yet easy to unscrew as needed). Using a small ruler, measure and slide the guide to obtain a wide range of seam allowance preferences -- from a scant quarter inch (1/4") seam, a true quarter inch seam, and more!