With the lightly twisted strands this allows the thread to both lay flat and split easier than other threads on the market. The amount of wax added has been specifically applied after consultations with top Professional Fly Tyers. Chart below provided to help you make the right section: Size Denier Breaking Strain       ( grm ) Breaking Strain       ( oz ) Hook Size Use For 6/0 150D 983gm 33.01oz 8 Large Salmon, Predator flies & Deer hair spinning 8/0 105D 754gm 26.6oz 6-14  Salmon, Predator Streamer, Nymphs & Dries 12/0 70D 489gm 17.25oz 10-20  Midges, Emergers and Dries 18/0 30D 390gm 14oz 14-32 Micro Flies