Aqueon Small Filter Cartridge for Mini Bow, Set of 6 Filter Cartridges Ready-to-use, preassembled filter cartridges install in seconds. Patented dual-sided replaceable dense-floss cartridges filter out more particles and debris Helps create crystal-clear, healthy water. For best results replace cartridge every 4-6 weeks Cartridges contain more activated carbon to remove toxic impurities, odors and discoloration. Fits Mini Bow 1, Mini Bow 2.5 and Mini Bow 5