Caterpillar 7W5040 7W-5040 ENGINE AIR FILTER Advanced High Efficiency Multipack (Pack of 2) Standard Efficiency Engine Air Filters are your best value for normal duty applications providing larger capacity and quick servicing. You can't control the environment you're working in, but you can keep your engine working longer by keeping the air inside clean. Cat&reg; Engine Air Filters are designed to meet strict standards and provide the best protection for your Cat engine. Primary vs Secondary: Primary Efficiency Rating: Standard Efficiency Seal Type: Radial Seal