?The Box-packed Fish Tank Aquarium Filter Media Ceramic Rings utilizes extremely porous ceramic media for best filter performance and aquarium water quality. It features a hollow design that effectively distributes water flow and removes debris from water. Meanwhile， it also allows massive colonies of beneficial bacteria to grow on and inside each ring. Designed to offer coarse filtration， it works great for both freshwater and saltwater aquarium applications. Don’t hesitate to order now! It surely is worth your investment!                                    Features             Utilize extremely porous ceramic media<br> Provide best filter performance and aquarium water quality<br> Hollow design effectively distributes water flow and removes debris from water<br> Allow massive colonies of beneficial bacteria to grow on and inside each ring<br> Great for both freshwater and saltwater aquarium applications <br>                                                            Specifications             Dimensions     (5.83 x 4.01 x 2.56)" / (14.8 x 10.2 x 6.5)cm (L x W x H)    <br> Weight     500g / 17.64oz     <br>                                                             Package Includes            1 x Packed Ceramic Consider Ring<br>