100 wt cottonized soft polyester. Tone on tone, InvisaFil virtually disappears. InvisaFil is perfect for stitch in the ditch, bobbin thread for delicate machine embroidery, top & bottom thread for couching, lace designs, hand & machine appliqué, quilting, longarming, and excellent for fine fabrics. Available in 60 colors on 2734yd (2500m) spools.