AquaClear 20 Zeo-Carb Filter Insert effectively eliminates odors, discoloration and impurities in freshwater aquariums, potent chemical duo prevents the buildup of toxic ammonia and nitrite, designed for Power Fil
Cube, Individual cubes for density experiments, Available in eight different materials: acrylic, aluminum, brass, copper, nylon, polypropylene, PVC, and steel, Each material is represented by a 1/2inch, 1inch and 11/2inch cube