RT/OBCON - 2003 Chevy Silverado and GM Sierra 1500 Extended Cab Dual 12" Speaker Box With Labyrinth Power Port Designed for: 2003 Chevy Silverado 1500 and GM Sierra 1500 51 1/8" wide x 15 1/8" deep x 9 1/2" tall "Tri-lock" joint construction (caulked, glued, and stapled) Speaker mounting depth: 5 3/4" - Air Volume: 1.20cf Labyrinth slot vent design (downfire)