UNI Thread 6/0 Thread - 6/0 UNI-Thread is a general fly-tying thread of continuous polyester filaments. The wide range of colors meets virtually all fly-tying needs. UNI has an exclusive waxing process produces a thin coating to reduce that annoying build-up of wax in your bobbin tube. Continuous polyester filament 6/0 135 denier size 50 yard spool waxed