I just bought new ones. The easiest way is simply to Google your make of A/C. For me, I Googled "Dometic A/C Filters" or "Dometic RV A/C". Do that and your search should turn up the filters. Ended up getting mine through Dyers RV Parts & Accessories (www.dyersonline.com). Like the previous poster said, though, if yours are still in good shape, just wash in soap and water. Mine were worn out and torn and no longer really usable.