I think the Spectre core is aluminum. Good price,but the one that I put in my car only lasted for about 10,000 miles. I went to a rad shop and had my original copper one rebuilt as the old guy who rebuilt it told me that you can't mix aluminum cores with copper rads as they won't last (chemical reaction between copper and aluminum). I don't know if this is true or not but I was just as happy to spend the extra money and get the original rebuilt.