SINGER Overlock Needles are used in sergers to sew over the edge of one or two pieces of cloth for edging hemming or seaming. Multiple sizes allow for the user to hem different types of fabrics. Color coded needle sizes include orange size 80/11 for use on lightweight woven fabrics blue size 90/14 for use on medium weight woven fabrics and purple size 100/16 for use on heavyweight woven fabrics. The needle kit comes in an easy-to-store plastic container with sizes marked on the cover for easy location and replacement. The SINGER overlock needles are for use on SINGER ProFinish Professional and other brand serger sewing machines that require 2022 needles.