Product review (5 stars): Great charcoal secondary filter
I am a big fan of these charcoal add on filters for non-duct usage.  They work great in conjunction with the standard aluminum mesh filters and are simply clipped onto the other filters.  These Broan filters fit perfectly on the QP series of range hoods which they were intended.  I see others complaining, but they are attempting to use on different hoods (?).  These definitely help subdue cooking odors and also keep the grease and oils out of the interior of the hood.  They will last over six months and are a quality product.