The RO Unit is a reverse osmosis unit designed specifically for fish tanks and aquariums. This product effectively removes impurities and contaminants from the water, providing a clean and safe environment for fish to thrive. By utilizing reverse osmosis technology, this unit ensures that the water in the aquarium is pure and healthy for the fish, promoting optimal growth and well-being. Perfect for pet owners looking to maintain clean and crystal clear water in their aquariums. Used but in good condition and perfect working order