-The OneSpot Treatment for Cats and Kittens stops the flea life cycle by killing and preventing flea eggs and flea larvae for up to 30 days. -Topical drops are a convenient once a month application. -Comes in 3 months supply.-Prevents flea population build up.-For Cats of all ages and sizes.-Hartz is a trusted flea and tick brand and has been providing flea and tick solutions for pets for over 50 years.