Sliver Metallic Thread. This thread is a ribbon-like metallic polyester film that features aluminium to make it brilliantly reflective and it is great for sewing machines, sergers and handwork. Works best on a vertical spool pin and a 80/85 14 needle (embroidery or top stitching). This package contains one 250yd spool. Available in a vast array of colours: each sold separately. Imported.