When fishing heavily pressured waters, you need a fly proven to bring the bite on technical tailwaters like the South Platte River in Colorado. Imitating a river's worth of mayfly and midge species, the Rainy's Chocolate Thunder Fly tempts untemptable trout into a fight they'll never forget. Foam wing and realistic profile produces with uncanny effectiveness. A fly proven to bring the bite on technical tailwaters Born on the South Platte River in Colorado Imitates a river's worth of mayfly and midge species Foam wing and realistic profile