To use an adjustable overcast foot on a sewing machine, watch this video sewing tutorial. It is ideal for stitching and finishing stretch fabrics or fabrics that unravel easily. Prevents seam from puckering, even when stitching wider seams. Turning the screw, adjust wire to seam width so needle swings over wire on right side. Stitch slowly with edge of fabric even with red guide and stitch going over wire.