[Sponge Pool filter type H]Length:8.8 cm/3.47 in; Outside Diameter: 7.8 cm/3.08 in; Inner Diameter: 2.8 cm/1.11 in. The pool filter sponge is suitable for type I pool filter pump, It is designed for filter pump item Number: 28601/28602.[Reusable washable filter] This Sponge pool filter sponge cartridge is made of sponge Replacing the filter paper filter is part of the daily maintenance of the swimming pool. Regular replacement of the filter may cause high costs. These washable and reusable foam filters will reduce your costs.[Good for your pump]: the sponge filter accessory will help to clean particles and debris so that it can prolong the life of your filter media, providing efficient water flow with less clogging for long lasting filtration and cleaning.[Durable] Regular cleaning every two weeks makes the foams more durable. The replacement time depends on the frequency of use and the actual situation of the sponges, normally it may last not less than 1 month.[Save time and effort]Changing the pool filter cartridge is part of regular maintenance for pool,this reusable washable hot tub cleaner tool is much easier to clean and maintain than traditional paper filters,save you lots of time and effortColour:blueMaterial:spongePackage Contents:4 x filter spongesOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.