Rene Harrop has spared no cost or effort in securing the very finest tying materials in the world. The quality of this CDC is unsurpassed by anything on the market today. You just have tie with these feathers to believe it. The Dark Dun is perfect for dark wings and sillouette patterns...caddis, small stoneflies, or mayflies. The bulk bags (3.5g) hold enough feathers to tie a couple hundred flies and is a great bargain.