Wonderfil Iron 'n Fuse Heat Fusible Vinylon Thread. Perfect for applique, lining up corners, matching up patterns, bindings, and zippers. Sew with it in the bobbin or have a fabric layer over the stitches before pressing to prevent thread from adhering to the iron. The heat of an iron will fuse layers of fabric together, holding it in place so you can perfect your project. 40wt 100 percent heat fusible vinylon thread, 1 color in 200yd spool. PUC-IRNFUS