20 Spool holders: they are used to prevent the thread from unwinding and the tail of the thread from getting tangled with other spools. In addition, they provide a good grip to maintain thread tension. SPACE SAVING: These wire racks won't take up much space in your wire racks and lockers. But with these items, you can just keep your spools neatly organized. FLEXIBLE MATERIAL: All of these items are made of high quality silicone, which is very flexible and very easy to open to accommodate different sizes of sewing threads and embroidery spools. NOTE: They are not suitable for commercial, industrial or large spools!!!! Reusable Design: After repeated use, these spools will always spring back to their original shape. Very durable for years of use. THE BEST GIFT FOR EMBROIDERY LOVERS: These items are the most satisfying gift for craft and embroidery lovers.