Official replacement foams are for use with the following External Aquarium Filters;

Aquarium External Filter 1000EF
Aquarium External Filter 1000EF plus
Aquarium External Filter 1400EF
Aquarium External Filter 1400EF plus
Aquarium External Filter 2000EF
Aquarium External Filter 2000EF plus
Aquarium External Filter EF1
Aquarium External Filter EF1+
Aquarium External Filter EF2
Aquarium External Filter EF2+
Aquarium External Filter EFX
Aquarium External Filter EFX+

1000/1400 L/H packs supplied with 3x foams, 2000 L/H's supplied with 4x foams.