Pre-Filters help to prevent sand, mud, and dirt, from contaminating the air filter in your 1992-2006 & 2009-2016 Volkswagen 1.9L/2.0L TDI. You can get the right pre-filter for your intake by matching up the filter dimensions or from the corresponding filter part number. XDP carries pre-filters from manufacturers such as AFE, K&N Engineering, and many more! 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.