Hartz UltraGuard Flea and Tick Collars kill fleas and ticks for seven months and are the most cost-effective method of protection against adult fleas. Collars have a clean fresh scent. Please be sure to always use dog products on dogs and cat products on cats as they cannot be used interchangeably. Hartz UltraGuard Product Comparison Hartz UltraGuard Hartz UltraGuard Plus Hartz UltraGuard Pro Kills Adult Fleas and Ticks for Immediate Results X X X Kills Flea Eggs Larvae and Pupae to Prevent Reinfestation X X Flea LifecycleFor every visible adult flea there are many more flea eggs larvae and pupae in the surrounding environment that you do not see. Treating infested areas as soon as the problem is recognized is vital in stopping the flea life cycle. Hartz UltraGuard Plus and Hartz UltraGuard Pro powders sprays and foggers quickly kill adult fleas and ticks and stop the flea life cycle -- halting the current infestation and preventing future infestations. The UltraGuard CommitmentHartz UltraGuard provides affordable convenient pest control for every pet. UltraGuard is committed to applying the latest science to effectively eliminate fleas ticks and mosquitoes and to prevent them from infesting pets and their surroundings. Uncompromised quality is our ongoing mission. At UltraGuard we recommend an integrated and complete approach to pest management. Our expertise in parasite protection ranges from on-pet topical drops shampoos and collars to in-home sprays carpet powders full-room foggers and in-yard sprays. Treating the whole problem is the key to a pest-free environment.