Gentle formula. Faster acting, longer lasting. Kills fleas, ticks, mosquitoes. Plus flea eggs. 3 Month supply. Hartz Advanced Care Brand Flea and Tick Drops Plus for Cats is the monthly treatment that effectively controls flea and tick infestations. This gentle formula kills and prevents adult fleas, ticks and mosquitoes, plus flea eggs and larvae thereby breaking the flea life cycle. It is also waterproof.