Farnam's Tri Tec 14 Fly Spray protects against horse flies, mosquitoes, lice, ticks, and all other flying nuisances for your horse's benefit. This spray is made of a water-resistant formula that works to repel bugs even when the horse sweats. Perfect for moist environments, Tri Tec 14 uses long-lasting ingredients that can repel and kill insects for up to 10-14 days. This bottle is a continuous aerosol spray.