Honeywell 38002 Universal Pre-filter Type: Replacement Filter Used For: Air Purifier Feature: The Honeywell Universal Carbon Pre-filter helps capture large airborne particles before passing through the HEPA filter, therefore maximizing the HEPA filter life. The activated carbon per-filter also helps reduce common household odors. Replaces pre-filter numbers 32002, 33002, 34002 and 35002 Should be replaced every 1-3 months of use Can be cut to make 1 to 3 pre-filters, depending on air purifier model Fits virtually all Honeywell Round, QuietCare and SilentComfort Series model air purifiers