does not fit. cannot be installed. Top filter opening is approximately 4-1/4. The removed filter is 4-3/8. Attempting to force it to the mounting plate will compress the side panel slightly and prevent the filter from installing the threaded stud that holds it tight to the suction head. Even yesterday, May 29, some filters were shown on which a photo indicating the opening of 4-38 was marked, but today they have mysteriously disappeared? what happened to you I would order one of these other brands if I could find them.