OUTERWEARS ATV PRE-FILTER K&N YA-4350 20-1009-01. The vendor part number is 20-1009-01. Read title carefully to know what you are getting. Here is the catalog descrion NOT the title? Dyno and flow bench testing has shown no significant loss of horse power or air intake while using this product Silicone impregnated micro-mesh is water resistant Seams are dielectrically welded Material contains uniform micron sized openings that allow air in, yet filters out the unwanted elements, such as sand, dirt, clay and even water Filters particles as small as .005" in diameter without noticeable air flow restriction