“Tetra Easy Crystal Filter Pack C100Tetra Easy Crystal Filter Pack C250/300Ultra-activated carbon absorbs odours and discolourationDense, dual-sided mesh catches debris and fish wasteFast, clean replacementNo need to rinse the filter medium, no more wet hands3 cartridges per packThe innovative Tetra Easy Crystal Filter Pack C100 is suitable for the Tetra Cascade Globe Aquarium Filter.The easy to change Tetra filter cartridge contains active carbon and provides multi action filtration resulting in crystal clear, healthy water. For best results change the filter cartridge every 4 weeks. The innovative EasyCrystal Filter Pack C 250/300 is suitable for both EasyCrystal Filter 250 and EasyCrystal FilterBox 300. With its intensive physical biological and chemical filtration, the filter cartridge ensures crystal clear, healthy water.Fast, clean replacement: For best results change the filter cartridge every four weeks. No need to rinse the filter medium, no more wet hands! Important: The filter cartridge must be placed into the filter with the green side facing towards the front of the unit.”