When Ford owned Mazda and Aston Martin in 2005, one shared part was the cabin air filter. The DB9 uses the same filter as the RX-8 and MPV, which means it is also open to the same aftermarket filters.
In addition to debris, this ATP unit also filters odors that the stock unit doesn’t. Also, this is $15.99, while an OEM DB9 filter is at least $50.
Enjoy fresh air in your DB9.