BERNINA OLD Appliqué foot #23 lets you sew even dense rows of stitches without a hitch -- ideal for appliquéing and sewing mini-piping, appliquéing narrow buttonhole seams up to 2 mm wide; simultaneous sewing of a reinforcing thread or ribbon, as well as for traditional sewing techniques. Smooth feeding, even with dense stitching. For 5.5 mm and 9 mm machines.