Intex 6 x 29001E B00PUZW3N2 PureSpa Type S1 Easy Set Pool Cartridges (12 Filters) | 2, 1 Pack, Blue Genuine Intex type S1 filter cartridge - twelve pack The S1 cartridge filter is sure to keep your purespatm jet massage water clean and fresh It is made with easy-to-clean, heavy duty Dacron paper, for the ultimate filtration For maximum efficiency, clean cartridges each week and replace once a month or sooner Each filter Measures 3in x 4 1/4 in Part #29001E