Marineland Penguin® Power Rite-Size™ Filter Replacement CartridgesThe Marineland Brand designs our filter cartridges to meet the absolute highest standards of water purification, performance, and operational ease. Each pre assembled cartridge slides easily into place, providing superior mechanical and chemical filtration, and making replacement fast, dry and effortless. The cartridge mechanically filters water through a pad of double thick poly fiber. Debris and waste particles are trapped, and water is chemically