Threaders Silicone Bobbin Holders Make sure that you keep your threads and bobbins safe and secure with the Threaders Bobbin Holders. These holders have been designed to slot into the opening on your thread spool, giving you a platform to add the matching bobbin in top. This will help you to keep matching colours together, saving you from having to hunt through your stash! Designed with the highest quality silicone, these bobbin holders will stick firmly inside the spool without slipping, keeping your bobbin secure. With 20 bobbin holders included in the pack, they pair up perfectly with the Threaders Bobbin Clamps to prevent any unwinding.