Probably one of our favorite flies that you can buy out of a bin, Coffey's Sparkle Minnow produces all the time. Chasing rainbows and browns in a blown out creek? High stick and jig a small size. Looking for that one bite from the biggest brown in the river? Fish the mid or large size on a sinking line.
This is probably one of, if not the most productive river bass fly that you can buy.