These were Factory filters in a new commercial air conditioner, as seen in the first photo. They fit well but didn’t filter all that well due to a low Merv rating. The 2nd photo shows the pleated filters with Marv11 rating for an upgrade. The third photo shows the new Merv 11 filters installed but with a gap between them.. We solved this problem in the last photo. We used a piece of wood as a spacer and taped the gap so that it is sealed around and between the filters.