Chevy Silverado / GMC Sierra Ext Extended Cab Single 12" Subwoofer Enclosure Sub Box 1999-2006, CARB COMPLIANT MDF! DONT BUY CHEAPER NON COMPLIANT MDF! Chevy Silverado/ GMC Sierra Extended Cab 1999-2006 Down-Firing (Fits Under Rear Seats), Single 12" Enclosure Volume: .90 Cu. Feet/ Mounting Depth: 6" High Quality Terminal Cups (accepts Banana Plugs or Bare Wire) Constructed of Industrial Quality Grade 5 MDF / Quality Black Wrapping Carpet This Enclosure Fits: 1999-2006 Chevy Silverado Extended Cab (Fits 2007 Classic Body)/ 1999-2006 GMC Sierra Extended Cab (2007 Classic Body)