Revive Offgassing Reduction Filter, Pack of 3, Brondell, Mfr#: PRF-58

One year replacement filter pack: Using a proprietary catalyst, the Specialized Off-Gassing Reduction Filter effectively removes invisible substances like formaldehyde and VOCs that contribute to “Sick House Syndrome” that can cause health and respiratory issues. • Standard Filter Pack and Humidifier Filters NOT included (sold separately)• Only for Revive: The Revive Off-Gassing Reduction Filter Pack will only work with the Brondell O2+ Revive models PR50-W and PR50-B• Other available Revive replacement filters: The Specialized Off-Gassing Reduction Filters (PRF-58) get changed after four months or as needed along with the Humidifier Filters (PRF-52). The Standard Replacement Filter Pack (PRF-51) is changed every year• Proud members of 1% for the Planet – Brondell donates 1% of annual sales to environmental nonprofits