Eprinex Pour-On contains eprinomectin, a macrocyclic lactone that disrupts nerve and muscle function in susceptible parasites. The clear, colorless liquid is applied topically along the backline of cattle at a rate of 1 mL per 10 kg of body weight. It targets gastrointestinal roundworms, lungworms, grubs, sucking and biting lice, mange mites, and horn flies in beef and dairy cattle of all ages, including lactating dairy cows. The weatherproof formulation remains effective on wet or dry hair coats and its efficacy is not reduced by rainfall. Smaller bottles include a measure-squeeze-pour metering system for calibrated dosing by body weight, while larger packs are intended for use with automatic dosing equipment. The product is formulated for external application only and should be stored away from direct light at moderate room temperature.