The Seresto Large Dog Flea & Tick Treatment Collar is a veterinarian-recommended solution designed for dogs over 18 pounds who are at least seven weeks old. This collar provides up to eight months of continuous protection by releasing a proven combination of imidacloprid and flumethrin that kills existing fleas within 24 hours and repels new ticks within 48 hours, effectively eliminating pests before they bite your dog . Its water-resistant design ensures it remains effective through bathing, swimming, rain, or sunlight exposure, maintaining protection even under wet conditions . The collar is odorless, non-greasy, easy to apply, and adjustable for a comfortable and secure fit using the two-finger rule . While generally well tolerated, occasional mild skin irritations—such as redness or hair loss—may occur at the application site; more serious reactions are rare, and the collar’s benefits are deemed by experts to outweigh the risks.