It's easy! No mess, no stress. Just clip'n go. Spectra SHIELD Collar Attached Medallions contain powerful ingredients to offer 4 months of flea and tick control for dogs. The medallion snaps on easily to the dogs collar so there is no mess and no stress! It is available in 3 different weight sizes. The medallion contains a powerful synergized pyrethroid - zetacypermethrin - that kills adult fleas and ticks at maximum efficacy. The second ingredient, Piperonyl Butoxide, is a mixedfunction oxidase inhibitor which ensures the maximum effectiveness of Spectra Shield against ticks during all stages of their blood- feeding life cycle.