SoundBox GMC Sierra/Chevy Silverado Subwoofer Enclosure Ext Cab Dual 12'' 1999-2006 Chevy Silverado/ GMC Sierra Extended Cab 1999-2006 Down-Firing (Fits Under Rear Seats), Dual 12" Enclosure Volume (Cubic Feet Per Chamber): .97 Cu. Feet/ Mounting Depth: 6" High Quality Terminal Cups (accepts Banana Plugs or Bare Wire / Quality Black Wrapping Carpet Dimensions: 51W x 9-1/2 FH x 7 RH x 13-1/2 D This Enclosure Fits: 1999-2006 Chevy Silverado Extended Cab (Fits 2007 Classic Body)/ 1999-2006 GMC Sierra Extended Cab (2007 Classic Body)