Definitive Technology RSS II Rough In Bracket (Single, Silver) Single reference in-ceiling/in-wall surround speaker in bracket Equipped with two 4.5-inch bass/mid drivers and two 4.5-inch planar pressure-coupled low bass radiators Frequency response: 26Hz - 30kHz Equipped with two 1-inch pure aluminum dome tweeters Outer dimensions: 11 W x 12.75 H inches