The Eureka ZVac HF8 HEPA Filter is superior replacement filter for the Eureka and Sanitaire Mighty Might canister vacuums. This is a 4 Pack savings Bundle. Meticulously designed to meet the exact manufacturer's specifications for size and quality, the Eureka ZVac HF8 HEPA Filter delivers a superior alternative to costly genuine and generic Eureka HF8 Filters. Replaces OEM part numbers: 60666, 60666A, 60666B The Eureka ZVac HF8 HEPA Filter will fit the following Eureka Mighty Might canister vacuums: 3684, 3685, S3686, and 3695 GoVacuum recommends that consumers replace the Eureka ZVac HF8 HEPA Filter every5 to 7 months in order to maintain optimal operating conditions. ZVac has engineered these HF8 HEPA filters with mostly earth friendly materials which make the filters mostly biodegradable, reducing their negative effect on the environment.