This set contains six 440-yard spools of 100wt, 2-ply cottonized polyester thread in tonal colors— perfect for all kinds of appliqué. It stitches like silk, melting into your fabrics. We use it for cotton, silk, and wool appliqué. Once you try it, we think you will love it! We use it for hand appliqué, but it works well for machine work, too.