Features: 1.Replacing the paper filter element is part of the daily maintenance of the tank. Replacing a conventional filter element can be very expensive. These washable and reusable foam filters will reduce your costs. 2.This foam filter can survive in the carton and can be washed and reused multiple times. 3.It is recommended to replace one carton per week, and these foams can be easily cleaned and replaced. You should see the foam filter last for about 2 months. 4.All you have to do is remove the filter when you impact the electrode rod, as excessive chlorination will cause the foam to rupture quickly. Normal levels of chlorine and bromine disinfection are good and these foams have been tested at normal levels. Size: S:9*10.2cm M:10.8*7.3cm Package List: 1 x Swimming Pool Filter