A20063 - Motor Seal Ring/Gasket for 304-404/306-406. A20172 - Magnetic Impeller - Flat Blades (404/405). A20156 - Fluval 305/405 Impeller Cover. Fluval 405 Magnetic Impeller(A20172) - with straight fan blades - also suitable for Fluval 405 External Filter (A216).
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