Invisafil is 100wt soft polyester 2-ply thread by WonderFil. It's strong, colorfast, and non-abrasive with a matte finish that disappears into the fabric. It won't be bothered by ironing. Use it as bobbin thread for delicate machine embroidery. Also great for machine applique, sewing, and quilting. Invisafil eliminates the problems associated with nylon invisible monofilament threads(have a very low melting temperature, discolor or "yellow" over time, and go brittle). Spools are 2500m (2734 yards). Available in 30 colors.