More on Amazon.com : http://www.amazon.com/gp/product/B003IHUX6S?tag=purrfectcatdi-20
Definitive Technology Di 4.5R Fire Rated Back Box for 4.5-Inch In-Wall In-Ceiling Loudspeaker
Definitive Technology Di 45R Fire Rated Back Box for 45-Inch In-Wall In-Ceiling Loudspeaker