Application Summary: 2004-2006 Chevrolet Silverado 1500 LS LT Z71 (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 6, 8); 2003-2006 Chevrolet Silverado 1500 HD Base LS LT (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2004 Chevrolet Silverado 2500 LS (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 Chevrolet Silverado 2500 HD Base LS LT WT (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2006 GMC Sierra 1500 SL SLT SLE Denali (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 6, 8); 2003-2006 GMC Sierra 1500 HD SLT SLE (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2004-2004 GMC Sierra 2500 SLT SLE (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8); 2003-2006 GMC Sierra 2500 HD Base SL SLT WT SLE (Bed Length: 78.0 & Bed Type: Fleetside & Doors: 4 & Body: Crew Cab Pickup & Cylinder: 8)