Clover Locking Stitch Markers are made of durable plastic and have a safety pin locking mechanism that ensures that they will not come undone. Use them to mark repeats in the pattern, increases, decreases, and other important points in your knitting or crochet. Removable wherever you are in the project, which can be very helpful. Use in the fabric you are making or on the knitting needles, depending on where you need the mark.