Floriani's Appli-Kay Wonder. A fusible.
Ok, I use Wonder-Under for most of my fusible projects. It sticks on hand-dyed/hand painted fabrics without stitching down the edges, it's easy to find and it usually worked. There has been a major problem with it this year, so maybe finding something else is a good idea. When I don't use Wonder-Under, it's because I need to reposition items (or over/under-lap them); then I use Steam-A-Seam II.
I don't have a roll of it on hand to compare the chemical makeup and see if it's more like Wonder Under or more like StitchWitchery. In the manner in which Appli-Kay Wonder works, it's closest to Steam-A-Seam II. Where SASII is sticky on both sides, Floriani's Appli-Kay Wonder is only sticky on one side. Fuse it the fabric, cut out your shapes, and stick them in place.
Why, then, with all these fusible products already available, is Roberta recommending the Floriani product?
She appliqued a Day of the Day quilt.. one where the pattern is both a skeleton-man and skeleton woman. (I can't find it online, though I'm sure it's there somewhere). She cut both figures out and fused them down, then buttonhole stitched around all the edges with variagated rayon thread and her normal micro-sharp #12 needles. No mess on the needles. No broken threads. No larger needles.
A fusible that's so clean that it doesn't effect the needles or threads? THAT is definately a COOL TOOL.