The Penn Plax(R) Cascade Power Filter Cartridge 3 Pack are the disposable carbon replacement cartridges designed for the Penn Plax(R) Cascade Power Filters. Changing your carbon filter cartridge on a regular basis will keep your water crystal clear. Features: Easy to change carbon filter cartridges Works with Penn Plax Cascade Filters Ensures crystal clear water with frequent use 3 Pack Cartridges Item Specifications: 80: Fits Cascade 80 Power Filter Dimensions: (8.25" x 3.75" x 2.25") 100: Fits Cascade 100 Power Filter Dimensions: (8.8" x 4.25" x 2.15") 200: Fits Cascade 150 and 200 Power Filters Dimensions (9.5" x 5" x 2.25") 300: Fits Cascade 300 Power Filter Dimensions: (3.35" x 4.7" x 4")