The Bionaire A0327W is the correct replacement foam pre-filter for the following humidifier systems:
The Bionaire A0327W Foam Humidifier Pre-filter is used to remove airborne contaminants and particles with Bionaire CP0305 and Bionaire CP0306 Humidifiers. Bionaire Humidifiers improve your indoor comfort level by reducing static electricity, improving your breathing ability, and protecting your furniture and wood floors from drying out and cracking.
The Bionaire A0327W Foam Humidifier Prefilter specifications:
For peak efficiency and performance, replace your Bionaire humidifier filter every 3 months.