With Darning foot #9, small holes and tears in fabrics practically repair themselves. The hopper mechanism, combined with the vertical spring, presses the foot firmly to the project, preventing the material from pulling up with the needle during sewing (flagging) and ensuring a neat stitch pattern.
The special shape of Darning foot #9 also makes it ideal for free-hand embroidery, quilting, and creating attractive lace and monograms.