"A" Size Filter cartidge.
Intex 10-12-15ft Filter Cartridges. Fits the Intex 108 and 208 Krystal Klear filter pumps and older models

Size 8" High by 4.25" Diameter (20.3cm x 10.8cm)

These Cartridge filters fit Intex pumps with model numbers 58603, 58631, 58623, 56635, 56637 and 59900. The Intex Size (A) filter is also the same size as the Bestway Size (III) filter.

Intex recommends that you change your filters every two weeks, in practice & especially during the summer when pool use is normally higher, you may find that your pump runs more efficiently.