The Fluval A236 is the correct replacement for the following canister filters:
The Fluval 106/206 Aquarium Bio-Foam Replacement is a replacement aquarium filter for the Fluval model 104, 105, 106, 204, 205, and 206 canister filters. The Aquarium Bio-Foam promotes efficient biological filtration in aquarium water and traps small particles and debris. This aquarium foam filter also provides an additional layer of mechanical filtration and is best suited for freshwater and marine environments.
Fluval 106/206 Aquarium Bio-Foam Replacement specifications: