Earl's 21310ERL 13 Row Oil Cooler -10 AN Manufactured in the U.S.A from aircraft spec aluminum alloy, using the latest vacuum brazing technology. Corrugated screen internal turbulator plates increase both thermal efficiency and mechanical strength resulting in the most efficient, smallest and lightest practical package. Manufactured from thin aluminum plates for the fastest possible heat transfer. Inlet and outlet fittings o-ring to the top plate assembly. Designed for the range of oil flows and air speeds encountered in high performance automobiles.