Prym Tailor's Wax is available as a practical round plate in a two-part transparent plastic box with three slot-shaped openings on both sides. If you pull the yarn through one of these grooves, it is coated with a fine layer of wax, giving it flexibility and stability. 

As a result, the thread slides smoothly through the fabric and is neither worn out during the sewing process nor can it become knotted. But not only thread, but also snagged zippers or jammed drawers can be made smooth again with the universal tailor's wax.