This MAZDASPEED sports air filter contributes to improved engine performance. For the NC Roadster. Compared to the genuine air filter, intake efficiency is improved by about 10%, and you can hear the intake sound a little. It has the same shape as the genuine one, so installation and removal are easy. It has been used for several years, so there is some dirt. Please understand that this is a used item and only those who can purchase it with no claims and no returns are welcome. I will clean it as much as possible with a vacuum cleaner before shipping. The box will be folded and packed. This is a discontinued product, so if you've always wanted to try it, take this opportunity. Thank you for looking.