This has been my #1 stonefly pattern for over a decade. I turn to this pattern whenever there are stoneflies present in the river or stream I am fishing. The Rowley Stone is tied with a heavy tungsten bead which helps it get down to depth very quickly. I fish it in a size 6 most of the time, but find size 8 to be useful when smaller stones such as Skwalas and Yellow Sallies are present (Golden), or if green drake nymphs are around (Dark).