2 Ozone Plates for Solair 3500 Pro and 3500 Elite Air Purifiers This durable ceramic ozone plate fits Solair 3500 Pro and 3500 Elite air purifier models. Size: 4 1/2" x 4 1/2" Ozone plate(s) will deteriorate over time. If your air purifier operates 24 hours a day, 7 days a week you should expect to replace your ozone plate(s) about every 1-2 years. Ozone plate(s) must be cleaned once a month. This ozone plate will also fit the following air purifiers: Lighting Air, Lighting Air Plus and Mammoth