The Bottom Line is a new colored polyester bobbin thread designed by Libby Lehman that virtually disappears as the top thread harmonizes with the bobbin thread. Imagine not having to worry about a stray white thread from the bobbin showing up on top with your beautiful embroidery thread! Imagine sewing with metallic thread on the top and a matching poly bobbin thread on the bottom. This 60 weight thread is a fine, lint-free filament polyester with a very shiny silk like finish. The spools come with 1420 yards of thread in 25 wonderful colors!