The "punch needle" is used to thread the needle through the yarn to create the stitching as an illustration. Used to prevent fraying of stitching, it does not harden and harden even when dry, making it easy to maintain the texture of the fabric. Dries to a virtually clear bond with no pungent smell. Air dry or iron on If you use the iron on it you can attach it strongly and it also comes with silicone paper (A4 size) that does not bond to the iron. Includes brush head for easy & even bonding application