The Bionaire 514 is no longer available.
The Bionaire 514 is the correct replacement prefilter for the following air cleaner models:
The Bionaire Foam Air Cleaner Prefilter 514 is a replacement foam pre-filter for the Bionaire Model BT400, BT500, BT500S, and BT501 Air Cleaners. This Bionaire air filter effectively extends the life of your air purifier's HEPA and carbon filters by removing large airborne particulates from your home. Bionaire recommends that you replace your air purifier filter every 3 to 6 months for optimum performance.
Bionaire Foam Air Cleaner Prefilter 514 specifications: