CSF High Performance Radiator - Manual Transmission | BMW N55CSF's factories are ISO certified, and are OE suppliers to many US, German and Asian manufacturers. When you purchase a CSF cooling product, you can be rest assured that it has been manufactured on the same production lines with the same high quality standards as their OE customers. Every single radiator is subject to rigorous testing procedures such as Hydrostatic Testing, Vacuum decaying and life cycle testing, and is designed to always be a "drop