Adams Flea & Tick Spot On for Dogs kills fleas, ticks, flea eggs, flea larvae. It also kills and repels mosquitoes. It provides flea and tick protection for dogs for up to 30 days and is water resistent. The Smart Shield Applicator is specially designed to make applying flea and tick control easier and more precise than ever before. The applicator’s ergonomic, contoured shape makes it easy to grip and the built in fin helps to spread the dog’s hair to allow the liquid to more readily reach the skin. Adams Flea and Tick Spot On Refill packages are for use with the Smart Shield applicators.