The XDP Duramax CAT Filter Adapter & Filter Delete O-Ring XD228 is a replacement O-Ring Seal for the XDP Duramax CAT Filter Adapter, or the XDP Duramax Fuel Filter Delete for your 2001-2016 GM 6.6L Duramax. While the original seal provides a long service life, having a replacement in your tool box is always a good idea. Many customers choose to replace it while rebuilding their fuel filter head, or freshening up other fuel system components as their truck ages. This is the large O-Ring that goes on the top of the XDP Fuel Filter Delete, or XDP Duramax CAT Filter Adapter and seals up against the surface of your factory fuel filter head. FEATURES: Includes (1) Large O-Ring Fits XDP Duramax CAT Filter Adapter XD171 Fits XDP Duramax Fuel Filter Delete XD163 WARRANTY INFO: Products manufactured by XDP carry a 1-Year warranty against defects in materials and craftsmanship. The Warranty is Limited to one (1) year from the date of sale and limited solely to the parts contained within the product's kit.