【Fitment】- Compatible with 2004-2014 E-150 / 2001-2005 Silverado 2500 HD / 2001-2005 Silverado 3500 / 2001-2005 Sierra 2500 HD / 2001-2005 Sierra 3500, with 6.6L Duramax LB7/LLY, Fits Automatic Transmission Models Without Engine Oil Cooler 【Specification】- Core Size: 27.3" x 17.91" x 2.75"; Inlet/Outlet: 1-13/16" / 1-13/16" 【Construction】- Made of High Quality Full T-6061 Aluminum Construction Core with 3-Row Tri Core Light-Weight Racing Design 【High Performance】- Stronger and Higher Capacity for Coolant than Stock Units, Improves Cooling by 35% to 45% Temperature, Makes Heat Dissipation More Efficient to Prevent Premature Engine Failure 【Installation】Direct Bolt-On OE Fitment or Replacement. No Instruction Included. Highly Recommend Professional Installer for Installation