Keep your filter safe from sand, mud, and other debris when you purchase a Pre-Filter to your cold air intake on your 1999-2003 Ford 7.3L Powerstroke. Purchase pre-filters from AFE, K&N Engineering, S&B, and many others at XDP! Find the right pre-filter for your intake system by matching up your filter part number, or by using the filter dimensions. Pre-Filters are installed over top of your air filter and serve as another layer of protection from airborne contaminates that could otherwise damage your filter, air intake, or engine. Pre-filters feature a breathable construction with a free-flowing material that allow your filter to breathe while blocking out large debris and contaminants.