A top dropper fly during buzzer (chironomid) hatches. Crunchers seem to split the jury as to how effective they are, personally on Grafham they’ve worked wonders for me during buzzer hatches and small black ones took lots of wild brownies on Scar House reservoir in the Dales a couple of seasons back. I’ve stopped tying them with the traditional peacock herl thorax, choosing a good furnace hen hackle instead.

Hook: Kamasan B175 #12
Tail: Furnace hen fibres
Rib: UTC ultrawire (red, green, chartreuse)
Body: Pheasant tail (melanistic and dyed olive)
Hackle: Furnance hen
Thread: Danville 6/0
Hot head: Globrite #12