This is a used original K&N air filter from a 2007 Saleen S281 Mustang. It has "SALEEN" embossed on the side and was the original equipment filter that came on those cars. Other than the Saleen branding it is no different and fits all 2005-2009 Mustang GT models. If your saleen is missing it's original air filter then this is for you as they are no longer made. If you just want to have a better reusable air filter for your GT then this also fits the bill.