The Olive Klinkhammer Barbless is an excellent, low-riding emerger for trout and grayling feeding on olive upwinged flies. Its curved olive body hangs below the surface while the parachute hackle and post hold the fly in the film.
Fish it during olive hatches with a drag-free drift. Match its size to the naturals and apply floatant only to the supporting hackle and post. This is the sort of dependable dry that can turn a quiet rise into a memorable take.