The ERD-8 is an 8-inch round stackable loudspeaker backbox or enclosure made of durable steel. It features a circular molded polystyrene damping pad installed on the inside top, secured with four welded tie-off straps. Designed for use in air handling spaces, it provides an internal volume of 262 cubic inches. The enclosure attaches to the tile bridge using twist tabs through the side flange. Suitable for audio applications.