Find a Pre-Filter for the cold air intake on your 2001-2004 Chevy/GMC 6.6L LB7 Duramax. Pre-filters from AFE, K&N Engineering, Banks, and others are all available at XDP. Pre-filters feature a breathable construction with a free-flowing material that lets air through while blocking larger contaminants. A pre-filter provides your vehicles engine, air intake system, and air filter with the protection it needs from large airborne contaminants while also helping to extend cleaning intervals. Find the right pre-filter for your intake system by matching up your filter part number, or by using the filter dimensions.