These knots are primarly used for attaching a fly line to a leader.
International Game Fish Association
Fly Fishing Fly Fishing Accessories Fishing Tackle Accessories - Ring O-ring Fly - Aliexpress
AnglerDream WF Fly Fishing Line Kit 1 2 3 4 5 6 7 8 9WT Fly Fishing Line Leader Braided Backing Fish Line Fluo Yellow WF 9F Fly Line Combo
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