Mark your sewing machine for Perfect Piecing every time! Position your needle for a perfect scant 1/4" seam. Great to use when you don't have a 1/4" piecing foot available. You can even use it to check the accuracy of your 1/4" foot. The Plexiglas guide is placed under the presser foot and needle is lowered through the hole in the guide so you can mark the perfect placement on the bed of your sewing machine using tape or sticky notes.