Steam-A-Seam 2 (double stick) has the pressure sensitive adhesive on both sides which allows for a temporary hold to both the appliqu? material and the background material. You can hold your project vertically and the appliqu? pieces stay in place and are still repositionable until fused with an iron. Once fused the bond is the same as the original Steam-A-Seam, unfinished edges won't lift or fray, if you choose to finish the edges you can sew through the pressed applique without gumming up your needle or finish the edges with paint. Washable and dry cleanable.