100% hand over-dyed cotton, with #3 being the thickest and #12 being the finest of the four weights generally used for applique. Each of these fibers is perfect for needlepoint - as well as a variety of other techniques, including blackwork, huck embroidery, tatting, quilt knotting, cross stitch, punch needle and more - and can be used on different mesh canvases. All four weights work well for the stitches on wool appliqué and penny rugs, too.
#8 is much finer, the appliquéd piece changes in appearance - and the wool's color, texture and shape become the focal point of the design, not the stitches themselves.