I've used these filters a few times and am happy with them. As far as I know they work (i.e. capture larger particles (dust) but still let air through) and don't cause any problems with my HVAC system. The only thing I'd caution potential buyers about is that they're slightly smaller than at least one other brand I've used (and therefore dangle a bit in the vent). The actual dimensions of these filters are 9-1/2" x 19-1/2" x 3/4" while another brand I've used is 9-13/16" x 19-13/ Measures 16" x 13/16". ".
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