Just like the Teflon in your frying pan, this foot is designed to be non-stick. The smooth Teflon surface stops fabrics sticking to the presser foot, preventing them feeding smoothly, causing puckering. Highly recommended for use with leather, pvc/vinyl, plastic, faux leather, oil cloth, etc. Fits most modern domestic machines using the common snap-on type presser foot, e.g. Janome, Brother, Singer, etc.