Bio Spot Defense with Smart Shield Applicator for Dogs and Cats ensures continuing long-term protection for your pet. Bio Spot Defense starts working in just 15 minutes to kill fleas, ticks, flea eggs and flea larvae. This fast-acting flea control treatment also kills and repels against mosquitoes. Bio Spot Defense flea drops are completely safe for use on dogs over 6 months of age and cats over 12 weeks, imparts a fresh, clean scent and contains lanolin to help condition your pet's coat. Bio Spot Defense Spot On Dog and Cat Flea & Tick Control prevents flea eggs from developing into adult fleas thereby controlling reinfestation for up to 2 1/2 months. Additionally it also kills fleas and ticks for 3 weeks and kills and repels mosquitoes for 3 to 4 weeks.