This is a pack of AquaClear BioMax Filter Media (A1370) used as the Stage 3 biological filter insert in the AquaClear 20 Power Filter System (A595).
AquaClear BioMax filter media for the AquaClear 20 Aquarium Filter System is enriched with oxygen to provide an optimum biological balance in your aquarium. AquaClear 20 BioMax also quickly enhances the reduction of toxic ammonia and nitrite to help your aquatic pets thrive better.
About half of your AquaClear 20 Bio-Max media should be replaced approximately every 6 months - it is not recommended that you replace all of the Bio Max filter media at one time because to do so would upset the balance of beneficial bacteria in your aquarium.
This pack of AquaClear Bio Max biological media is also known by Hagen part number A1370. It can be used in both freshwater and marine aquariums.