Spectra Shield collar attached medallions contain powerful ingredients to offer four months of flea and tick control for dogs. The medallion snaps on easily to the dog's collar so there is no mess and no stress! The medallion contains a powerful synergized pyrethroid - zetacypermethrin, that kills adult fleas and ticks at maximum efficacy. The second ingredient, Piperonyl Butoxide is a mixed function oxidase inhibitor which ensures the maximum effectiveness of Spectra Shield against ticks during all stages of their blood-feeding life cycle.