Cold Air Intake for 2001-2004 Chevy / GMC Duramax LB7 6.6LMAXIMUM PERFORMANCE Our cold air intake for the 2001 2004 Chevy GMC Duramax LB7 6. 6L was engineered to minimize air restriction and flows 44. 63% better than stock. This kit comes with a fully enclosed airbox that protects the filter from dirt and keeps out engine heat. PROTECT YOUR ENGINE This kit comes with a massive, highly efficient air filter which results in better performance and protects your engine. Available in either 8 layer Cotton