This little Ceramic Tubing Shaped Aquarium Ornament has two size options available, perfect for use in small and medium size fish tank (5-50gallon). Bigger one - 3 X 2.75 X 3 inch, 4.6 oz Interior diameter - 1.25 inch Smaller one - 2.13 X 2.75 X 2 inch, 3.2 oz Interior diameter - 0.75 inch Your betta fishes, shrimps or other small creatures can go in and out this tubing-shaped ornament to sleep, rest or hide. It is made of breathable and porous ceramic media, which is good for efficient biological filtration as beneficial bacteria may accommodate on the surface to remove toxic ammonia and nitrite in your aquarium. (Beneficial bacteria is not included, you may need to purchase separate beneficial bacteria for this purpose). This porous ceramic media is also good for raising some kind of aquatic plants, such as Java Moss, Java Ferns or any other plant who like climbing to grow or has rhizomes to grow.