I fished these for the first time in the back eddies of the Green River below Flaming Gorge Dam at the beginning of October. The water was exceptionally clear, the sky was bluebird bright, and the fish were quite wary. Small BWO's were coming off in these eddies and the fish were feeding aggressively on them. But they were not keen on most offerings. When the guide I was fishing with tied on one of these, it was game on! We caught double-digit per rod numbers of nice trout each day for the next 2 days using parasol emergers in the slack water and foam terrestrials in the faster water.