A screw-in zipper foot is a sewing machine foot designed to sew close to zippers, piping, or edges with precision. It attaches to the presser bar using a small screw, allowing you to adjust the foot to either side of the needle for perfect alignment. This adjustable design makes it easy to stitch neatly alongside zipper teeth or bulky seams without the foot getting in the way. Ideal for both light and heavy fabrics, it helps create clean, professional-looking finishes. Commonly used in garment making, upholstery, and bag production, it ensures smooth and accurate zipper installation every time.