THIS ITEM IS NOT LONGER PRODUCED AND NOT LONGER AVAILABLE Replacement prefilter to fit certain Honeywell electronic air cleaners. Note that some models require 2 prefilters and they are sold singularly. Aluminum mesh prefilter is roughly 3/8 thick. 23 1/4 x 11 1/4. Measure your existing prefilter to verify this is the proper part number if you have an older model.