Marina i110/i160 Filter Cartridges - 6 Total Cartridges(3 Packs with 2 Cartridges per Pack) Provides mechanical, biological, and chemical filtration Polyester foam traps fine debris; carbon removes pollutants and odors; and zeolite eliminates toxic ammonia Easy to replace Designed to fit the Marina i110 and i160 Internal Filters (A301, A306)