Fluval Drain Valve External Filter FX4, FX5 and FX6, Pack of 1 : Amazon.co.uk: Pet Supplies
Fluval FX6 minimum space needs? | The Planted Tank Forum
Fluval - FX4 and FX6 canister filters feature a multi-functional Utility Valve drain at their bases, allowing you to empty the canister and perform seamless water changes with it! This means less