The Hagen A1396 is the correct replacement insert for the following filters:
The Hagen AquaClear 70 - A1396 Foam Insert - 3 Pack is an economical three-pack of replacement aquarium filter inserts for the Aquaclear 70 and 300 Power Filters. These foam insert filters capture particles and debris within aquariums and are tailored fit to prevent water bypass. The Aquaclear A-1396 is compatible for use with 20 to 50 gallon aquariums. Biological filtration is enhanced through these foam aquarium filters, which are also safe for use in fresh water and saltwater.
Hagen AquaClear 70 - A1396 Foam Insert - 3 Pack specifications: