Mettler Seracor Serger Thread, formerly called Metrocor Serger Thread, is an uncomplicated and reliable polyester serger thread that is predestined for classic work. A strong heart wound with fine fibers makes this a true all-rounder. 2-Ply Seracor is strong and resilient to resist breaking and produces even and regular seams on all types of fabric. It is shrink resistant. 50wt Polyester Thread.