"I don't know what this pattern is designed to mimic (it hardly resembles a hopper in anything but silhouette) but it upsets the fish enough to smack the heck out of it.
The foam causes it to ride high in the water even through chutes. It it easy to spot and the strikes I have gotten off of it are hard to miss. Most of the time the trout will whack it with their tail then come up on it and blow it out of the water.
