Product review (4 stars): Glad I found this
I have no idea what kind of exhaust fan is in my 1954 kitchen. I didn't even know that it needed a filter. There wasn't one when I bought the house. You could look up through the grill cover and see the dirty greasy fan blades. It worked, but I didn't like to use it unless things got smokey. I was looking for a filter for something else and this filter popped up. I would have given it a 5, but the center hole isn't quite big enough to slip over the center bolt. I was still able to tighten the nut to put grill back on though. Now I don't get grossed out when I look up.