Marineland Bio-Wheel Penguin Power Filter Cartridges provide premium activated carbon for efficient mechanical and chemical filtration, keeping your water crystal clear and clean. Rite-Size C cartridges are easy to replace and designed for maximum water contact.
Inside the filter cartridge, a patented ribbed backing ensures the even distribution of activated carbon to deliver maximum water-to-carbon contact. There is no "tea bag" effect and no water bypass as with loose or bagged methods. Contains Marineland Black Diamond Premium Activated Carbon.For best results, change cartridge every 2-4 weeks.Fits: Marineland Penguin Pro 275 and 375 Power Filters.Rite Size C Filter Cartridge Dimensions: 6.5"L x 5.8"W. Filter Cartridge Placement: Black plastic side faces the front of the filter, blue side faces back.