Apparently lots of them currently on the market - avoid the cheap offerings on ebay .
This might help identify the [URL="http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html"]FAKE[/URL] offerings
This might help identify the [URL="http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html"]FAKE[/URL] offerings