EHEIM Coarse Filter Pad (Blue) for Classic External Filter 2211 6 Total Filters (3 Packs with 2 per Pack) EHEIM Coarse Filter Pad (Blue) for Classic External Filter 2211 Incoming water is treated and pre-cleaned before it flows through the rest of the cleaning process Large debris are trapped, Rinse off pad and reuse For use in EHEIM Classic 2211