OFF! ACTIVE Insect Repellent Spray effectively repels mosquitoes that may carry dengue, malaria, encephalitis and West Nile virus. Provide hours of effective protection against mosquitoes (up to 5 hours), gnats and biting flies (sand flies, stable flies and black flies). Also repels ticks, chiggers and fleas from treated clothing. OFF! ACTIVE Insect Repellent is not greasy, won't stain and resists perspiration.