The Fluval Replacement Rubber Adapter for ribbed hosing comes in a pack of two and is suitable for the Fluval 304 External Power Filter (A210), the Fluval 404 External Power Filter (A215), the Fluval 305 External Canister Filter (A211), the Fluval 405 External Canister Filter (A216), the Fluval 306 Canister Filter (A212) and the Fluval 406 Canister Filter (A217).