The wulff is a deadly pattern for lake fishing and river fishing during mayfly time. They also work as an attreactor for small rainbow trout fisheries when the fish are up and a large bright dry fly is called for.
If you are fishing the mayfly these flies are really some of the best imitations around. The green and the grey are the most popular and a more bright yellow on a sunny day or on loughs like conn were a small bright mayfly seems to be the norm.
When mayfly hatch they can be anything from a cream colour grey or a bright green depending on the lough you are fishing. For example the mayfly that hatched on lough erne in May can be slightly different to the Mayfly that will hatch later in the year in July and August. This sounds very tiqunical but is is just to show you that grey and green cover most needs and if you start with these flies you wont be far wrong on any lough or lake. They stick in the surface and the wings stand out and creat a shadow similar to the real thing.
Here are some videos to help you tie the pattern. You can get the materials by signing up to the subscription or the flies if you dont tie.
Have a look through the videos and find the ones you need.