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