Filters work as advertised. The filter is mounted in the ceiling. When the fan starts the filter is sucked into the housing and drops down when the fan stops.
I receive them timely and undamaged. I can't tell how well they work but I can tell they are substantially better quality in design and execution than those grocery store brands. It really IS going to filter versus just fill that space. I have happy and feel I have made a good decision for my air quality!