Product review (4 stars): Air "de-odorizer" is probably more accurate
The word "filter" is a little grand to describe the function of this product.  It's as much an air "filter" as an open box of baking soda in the back of the fridge would be.  It's a bit of activated charcoal that removes odors from the air the same way the box of baking soda does.  But the air does not in any way get cycled through the filter.  It just sits there and absorbs the odors that waft over to it, carried on the the normal air currents within the fridge.

But - it does seem to get the job done, and it's a more elegant solution than a box of baking soda in the back of the fridge.  It seems overpriced to me, but I'll probably keep buying them anyway.