Bests & Worsts Reviews from Amazon

The carbon particles were loose and detaching from the filter. !!! This is of HIGH concern as it was on the exist side of the filter. Approximately 25% of the particles were missing from filter and loose in the package. Installed in furnace this would result in carbon particles directly entering a furnace combustion area - BAD BAD BAD- will potentially DEGRADE and contaminate A FURNACE BURNER. Do not recommend taking the risk regardless of the filtration. Not what I would expect from a Filtrete or 3M filter.