Formerly known as Metrolene, Seralene is a 100% Polyester Overlock thread that is perfect for creating fine, almost invisible seams on lightweight fabrics. Thanks to its fine qualities, Seralene is suitable for high-quality basting as well as for invisible stitching and decorative work. It also makes an ideal under thread or looper thread. Shrinkproof & easy to clean. Recommended needle size: 70-80. 2000m/2187yds per spool. 4 spools per box. Purchase by the box.