Sewing with knit fabric has always been a difficult task. This foot helps greatly with puckering, thread skipping and thread breaking. This knit foot has holding teeth that holds the fabric at just the right moment as the needle is going down through the fabric. The foot is designed to work with your machine's needle bar. As the needle bar goes up, it lifts the lever on the knit foot which pulls up the holding teeth and allows your machine's feeding system to advance the fabric forward for the next stitch. A wonderful foot to have around for sewing on T-shirts and other knits.