The Classic Waxed 12/0 tying thread is part of the Semperfli 12/0 70 denier Classic Waxed Threads (CWT) range, which has been specifically designed for tying midges, emergers and dry flies, typically used on hook sizes 10 to 20. Many tyers prefer our 12/0 thread over traditional 8/0 because it remains strong with a breaking strength of 489 g, yet has a finer profile. Semperfli has worked extensively with professionals to achieve the right amount of wax on each thread to hold materials in place without clogging your bobbin holder. It flattens easily and allows bump-free wraps.