The Double Decker was originally born as a comparadun style fly for river fishing and catching rising fish in shallow and fast water. The profile of the fly ensures that the deer hair wing is highly visible yet the deer hair body and coq de leon tail is sumberged- giving the profile of a hatching fly. Not only is this fly highly effective for river fishing but is now very popular on the stillwater scene. This is due to the "hatching" profile when the fly is laid flat on the water. It is a great immitation for hatching buzzers.
This is also a fantastic to use in a sedge hatch.