BTW I DON,T KNOW WHO SELLS THESE, oil cooler fins BUT IVE GOT TWO ON MY CORVETTES , I purchased decades ago on my OIL FILTERS AND THEY EASILY REDUCE OIL TEMPS 7-15 DEGREES,the ones I have are about 6" long and fit about 90% of the diam of the filter ID love to buy a couple new ones because they are a cheap and effective way to drop oil temps if you install them on a PF35 oil filter
notice this LINK POSTED says NOT IN PRODUCTION "Manufacturer has currently ceased production."
http://www.mesaperformance.com/web_store/web_store.cgi?page=accescat/coolers.html&category=yes