Features of the WD40, Brown
A relatively new fly compared to many, the WD40 came on to the scene and has proven itself quickly as a fly to fish.
An effective fly fished in the surface film, just under the surface or swept up from the deeper zones.
The Brown WD40 is a fly to have when you're fishing tailwaters, spring creeks, and waters with good concentrations of midge and mayflies.
You should not venture out without some Brown WD40's in your fly box.