Existing threads are often too bulky for tiers who work with hooks smaller than size 20. UNI Products, the leader in innovative spooled materials, comes to the rescue with our new 17/0 Trico thread. This extra-fine, white, polyester thread, is amazingly strong for its diameter. Perfect for caenis, trico, tiny baetis, and micro-caddis patterns. UNI Trico (17/0) is available on 200 yard spools.