Aqua One 401s Blue Sponge Pads – For Advance 550/750 Canister Filters – 2 pack

A new 401s twin pack of blue coarse Aqua One Sponge for the Aqua One Advance 550 and Aqua One Advance 750 external Canister filters. Open cell foam makes superb water filtration material because it both traps debris and acts as a good home for nitrifying filtration bacteria.