RT/OBCON - 2008 Chevy Silverado and GM Sierra 1500 Crew Cab Dual 12" Speaker Box With Labyrinth Power Port Designed for: 2008 Chevy Silverado 1500 and GM Sierra 1500 Crew Cabs (DOES NOT FIT HD MODELS) 50.5" wide x 15.5" deep x 9" front hieght x 7" back height - Premium 5/8" MDF "Tri-lock" joint construction (caulked, glued, and stapled) Speaker mounting depth: 5 3/4" - Air Volume: 1.00cf Labyrinth slot vent design (downfire)