Coats Secura Heat Activated Button Thread creates a super tight seal that can eliminate the problems of loose or lost buttons. If you're tired of buttons coming loose or popping off, you are going to love this thread. It sews like regular thread, but the secret comes when you're done sewing. Steam the sewn button from the back for just a few seconds and the heat activates the thread's coating, allowing it to stick to itself. It doesn't stick to the fabric or the button, just to itself. 100% polyester. 100 yard. Praline.