APOLLO Central ERV Secondary Activated Carbon HEPA Filters — Pack of 2APOLLO Central ERV Secondary Activated Carbon HEPA Filters Pack of 2 Replacement secondary filters designed for the APOLLO Central ERV. These activated carbon HEPA filters help improve indoor air quality by supporting fine particle filtration and odor reduction as part of the ERVs multi stage air filtration system. Key Benefits Designed for the APOLLO Central ERV Helps filter fine airborne particles from incoming air Activated carbon layer helps