Havahart Dr. T's 4-Pound Nature Products Snake Repelling Granules EPA-registered granules repel poisonous and non-poisonous snakes 4 lb resealable bag covers .5 acre and lasts 2 to 3 months Apply granules around the perimeter of area you want to protect 91% repellent rate of garter snakes and rattlesnakes Temporarily disrupts snakes sensory reception without harm