PROMOTION!!!2 packs (4 pieces) for only $4.90!!!Sponge cartridge contains active carbon for removing odour and keeps water clearEach pack contains 2 pieces2 packs (4 pieces) for only $4.90!!!* JENECA XP-09 Filter ~ require 2 cartridges* JENECA XP-11 Filter ~ require 3 cartridges* JENECA XP-13 Filter ~ require 4 cartridges