Innovative 2-core in-series system. Front full size core has 17 cooling tubes versus OEM 15 tubes. Secondary in-series backside cooler has an additional 6 rows of cooling. Made with 1-row super-high pressure 26 mm multi-channel microtube. High-density multi-louvered fin design for maximum surface area contact. An additional half quart of engine oil is required for proper oil level after installation.