A cripple-style Baetis mayfly for the smallest hatches. The crippled profile suggests a dun trapped during emergence, a trigger for selective trout.
At #20 it matches tiny Baetis adults. Fish it on a dead drift with fine tippet during heavy emergences.
When trout refuse a high-floating dun, this low-riding style often gets the nod — it sits in the film the way a real mayfly does.
