This ultra-light polyester waxed thread is designed for midge flies (size 18 and smaller hook). It lays flat on the hook and is a 2-strand thread which lays flat and, despite its size, splits easily for dubbing loops. The finest of the Semperfli Classic Waxed Thread series, the 18/0 thread measures 30 denier and has a breaking strength of 13.7 oz. (390gm). 240 yards (220m) per spool.