Virbac Knockout Area Treatment Spray is an aerosol house spray containing synthetic pyrethroids to quickly kill adult and larval fleas and ticks. Prevents subsequent flea infestations for up to 4 months (120 days). Pyriproxyfen (NYLAR Insect Growth Regulator) inhibits flea growth and kills fleas before they reach the adult biting stage. Available in 14 oz aerosol can. Covers approximately 2,000 square feet.