EMPI Pre-Filters feature a patented Micro Mesh Nylon filtration system that stops sand and dirt before it gets to your air cleaner element. Elastic base stretches over your air cleaner for a snug fit with no air restriction to speak of. It installs with virtually no carb. adjustment. Price is for 1 pre-filter. If you're running dual carbs, you will need to purchase 2. Pre-filter dimensions are 5 1/2" x 9" x 3 1/2".