25sqft – fits Dynamic Filter Series II and III, 50sqft – fits Clean & Clear/ Predator Filters, 75sqft – fits Clean & Clear/ Predator Filters, 100sqft – fits Clean & Clear/ Predator Filters, 200sqft – fits Clean & Clear/Predator Filters, 50sqft – fits Rainbow Dynamic/ Dynamic Filter Series II and III, 420sqft – fits Clean & Clear Plus Filters