Sweat-Resistant Protection. Provides sweat resistance for heavy workouts in the hottest, most humid weather. Protects against biting and nuisance flies, gnats and mosquitoes (Culex species). Repels and kills mosquitoes that may transmit West Nile Virus. Water-based formula gives horses’ coats an oil-free shine without attracting dust. Citronella-scented spray stays active for up to 14 days.