Undersized, flimsy inside construction.
This filter is undersized, period!  I bought five of these over a year ago and had to use newspapers to fill the gap.  If it says 16x25x4, that's what it should be.  Also, the inside frame is flimsy as it only used cardboard for support as oppose to metal wiring.  This means the folds are not at all uniformed which I suspect affects the performance of the filter.
Rating: 1 stars