Product review (2 stars): Not as expected.
The theory behind this product is sound but they do not work as expected.  First, the filter does not fit on the mounting even though I ordered the ones that were supposed to fit the hood assembly; I got the filters to hook over the top and put a small bungee between them to hold them to the sides of the motor.  Second, the carbon does not seem to effectively filter cooking smells and it should.