Product review (5 stars): Grease Is The Word!
I am having a custom-made grease filter housing made, and I'm using these as the custom-fitted filters for it. So, as a result, I can't speak to whether or not they are perfect replacements for Broan, JennAir or Whirlpool filters. They do appear to be well-made, and the washable and reusable feature was what I wanted to minimize future spending.

These will filter grease before the exhaust air enters the garage.  I'll update this review after the housing is made and the filters have been in service for a while.