The mobility of dogs and cats makes it difficult to treat all potential areas of flea infestation. So, it's important to consider a flea control formulation that goes where they do - especially one that targets pre-adult fleas, the source of reinfestations. Petcor® Flea Spray contains Precor® IGR, an Insect Growth Regulator that targets flea eggs on the animal by sterilizing them. - Contains natural pyrethrins to immediately kill adult fleas. - Precor IGR, an Insect Growth Regulator that kills flea eggs for 63 days after application. - An effective addition to a flea control Integrated Pest Management (IPM) strategy. - Approved for use on dogs, cats, puppies and kittens. - Convenient - after you deliver it as part of your service, customers simply apply Petcor by spraying as needed.