I designed this pattern like the Mask mayfly Olive,firstly with just a wing of natural deer hair. I later added an underwing of natural CDC so that when you false cast a few times the fly, fished on the top dropper, will sit like a dry fly in the surface film if fish are feeding on top. A great pattern for the top dropper it is fished, and has proved succssful all over Ireland. (See also Mask Mayfly Olive)