Large: dogs over 18 pounds. Find the right collar for your dog Use your dog’s weight to determine which size is right for them. Adjustable size allows for a custom fit. Non-greasy, odorless, easy-to-use. Starts to repel and kill fleas within 24 hours of initial application. Provides 8-months of continuous flea and tick prevention Seresto remains effective following a shampoo treatment, swimming or after exposure to rain or sunlight. Under normal conditions, effectiveness lasts for 8 months. Veterinarian recommended.
