CSF BMW E9X M3 Triple Pass High-Performance All-Aluminum RadiatorCSF manufactures the most advanced and efficient radiator in the industry for your E9X M3. CSF uses innovative tube and fin technologies with industry leading testing methods to maximize airflow and heat dissipation. 2 Row 42mm Core (Dual Core) Featuring CSF's Exclusive B Tube Technology Core Features an Ultra Efficient Fin with 6. 5mm Fin Height and Multi Louvered Design for Maximum Surface Area Contact Triple Pass Flow Structure Allows the Coolant