The Sizzlin Hot Spot Squirrel is a nymph pattern with a bright hot spot built in. The #16 sizing and hot spot trigger make it a useful attractor in a nymph rig.
Fish it subsurface under an indicator or in a Euro-nymphing setup, where the hot spot helps trout pick it out in fast water.
Adjust your indicator depth until the fly is riding just off the bottom, where nymph-feeding trout do most of their hunting.