Aquarium Masters Replacement Aquarium Carbon Filter Cartridge for Whisper Power Filter 20i, 40i, C 20, 30, 40, 60 & The Old Top Fin Power Filter 20, 30, 40, 60, Model 55! Replacement Carbon Filter Cartridge for Whisper Power Filter 20i, 40i, C, 20, 30, 40, 60 & Top Fin Power Filter Old 20, Old 30, Old 40, & Old 60, & Aquarium Masters Model 55! This replacement filter cartridge is a Multi-Stage disposable cartridge: Stage One is mechanical - Advanced multi-layered polyfiber floss traps micro & macro organic particles and foreign debris. Stage Two -Chemical -Super-Activated carbon granules absorb many disolved containinants, odor, toxins, and discoloration. Stage Three Biological ( Sold separately) - High-flow bio-sponge promotes colonization of beneficial bacteria essential to a healthy aquatic environment Easy to use & disposable. No mess cartridge handle & single-piece construction keeps hands dry & clean during cartridge changes High-Strength plastice frame for increased cartridge rigidity. Media-Grid ensures distribution of carbon granules throughout the cartridge for maximum filtration & flow Other Aquarium Masters & Blue Spotted items to consider, air line tubing, fish net, submersible heaters, refugiums, nirate pad, ammonia pad, polyfiber pads, power filters, air stones, bio-rings, UV sterilizer, heat pads, & heat lamps