Advantage II Ferret is a vet-recommended, leading brand in pet flea treatment and prevention Easy-to-apply monthly topical flea prevention and treatment for ferrets, 1+ lbs. and 10 weeks old – no prescription needed Same-day effectiveness – kills fleas within 24 hours of application and keeps working for 30 days Delivers total flea protection – kills adult fleas, flea larvae and flea eggs through contact Fragrance-free and waterproof after 24 hours of application