PYthon II Dust is the only dust that contains both Zeta-cypermethrin and Piperonyl butoxide. Zeta-cypermethrin is a 5th generation pyrethroid that is highly active against horn flies, face flies, ticks and other pests. Piperonyl butoxide helps overcome metabolic resistance in insects and synergizes the Zeta-cypermethrin for maximum efficacy and residual activity. PYthon II Dust contains a photostable formula for long-lasting activity in sunlight.