According to kind they combine mechanical, biological and adsorptive filtering.
You will get the filter mats by EHEIM exactly suitable for your filter. Thereby you save a lot of time with cleaning. Be sure: you can count on the checked quality.
The porous material is evenly filled by the water and holds on coarse and finest dirty particle. After a short finish time the cleansing bacteria which provide for intensive biological pollutant dismantling settle in the structured special foamed plastic. The mats are usable several times. To the cleaning one should only rinse them and express, so that the bacterial cultures are not completely destroyed.
filter mats for internal filters
filter mats for external filters