Bio Media made of Ceramic is a perfect choice for sump owners who are looking for material that allows easy passage of water. These ceramics are also extremely porous allowing a huge amount of surface area per ring for beneficial bacteria to live. Specifications: - Size of filter media bag: 8 " x 5.5 ". - Size of ceramic ring: 11/16" x 5/8". Includes: - 300g bag of Premier Ceramic Rings Caution: * Remove cloth bag with rings inside from the plastic outside packaging. * Wash bags thoroughly prior to putting ceramic rings into any aquarium system. Shipping Weight: 11oz. Handling Time: 1 day