Wapsi UTC Ultra Fly Tying Thread 70- The UTC Ultra Thread 70 denier nylon lies flat for less build upon the smallest trout patterns. This is a great thread for thread bodied nymphs and midges. UTC Ultra Thread has a breaking strength of approximately 1lb. and is recommended for size 14-32 flies. It is a similar denier to the Danville 6/0 and the UNI 8/0. Breaking strength is 16 ounces.
UTC thread color chart.