This Czech nymph style pattern works extremely well in many situations, but I've found it to work especially well in freestone streams in the late spring and summer. The tungsten jig hook causes the fly to bounce along the bottom, while not getting snagged. This fly fishes well with a dropper fly tied off the eye as well!

Materials:

Hook: Umpqua C400BL Size 10-14
Bead: Slotted Tungsten Bead
Thread: UTC 140 Denier
Head: Hareline Dubbin Pearl Core Braid
Collar: Whiting Brahma Hen or Partridge Feather
Hackle for Case: Strung Brown Saddle
Case:Hareline Dubbin Hare’s Ear Dubbing