The Elite Hush 55 foam inserts are an effective mechanical media that removes debris from the aquarium. The inserts encourages populations of beneficial bacteria that are important in maintaining the proper biological balance in the aquarium. Removes debris from the aquarium Inserts encourages populations of beneficial bacteria Inserts help maintain proper biological balance in aquarium Five foam inserts per pack Dimensions : 30.5 x 10.2 x 17.8 cm Made in the USA