The Adams Plus Flea & Tick Collar for Large Dogs and Puppies kills adult fleas, ticks, flea eggs and flea larvae for up to 7 months. The active ingredients are distributed through the coat and skin to cover the entire body. For continuous flea and tick protection under normal conditions replace the collar every 7 months. It’s waterproof so there is no need to remove the collar when swimming or in the rain. Do not use on puppies younger than 12 weeks of age.