One thing always leads to another. This great Baetis nymph owes a big thank you to Durango's WD–40 by Mark Engler. Noted Guide, "Boomer" Stout altered and tinkered and fished with the same design theme for the famous Baetis hatches of the legendary Green River. The satisfied smiles of his clients were frequently the result of Boomer's years of success with the resulting WD–50. He added an emerging wing case of the same duck flank (Wigeon, etc) used in the tail. For attraction he added the flashback over a chunky, dark thorax. This fly just seemed to trigger more strikes. Since Baetis are found nationwide, the olive and the gray are poised for success in fly shops coast to coast. Boomer especially proclaims the effectiveness of this fly during the first hour of the Baetis hatch. It is during this early stage that the biggest resident trout will briefly inhale the active nymphs before again vanishing back to their deeper holes. For these fish, this is Boomer's go to fly. So whether big fish or small, whenever the hatch causes fishermen to grab for a heavier pair of capilene undies, this pattern is a "fly for all reasons."