In order to ensure the cooling capacity, even under extreme physical conditions, Nissen has for a number of years manufactured radiators with double-folded fins. These are much stronger than the more common single-folded fins, resisting dust, stones thrown up from the road etc. much better. This reduces the risk of damage which would affect the cooling capacity and engine performance negatively.
Additional fitment speicification:
2004-2009 SL600 Primary Radiator