Furnace Filter Cover?

AllergyZone Azfl-100 Filterlock Furnace Filter Slot Seal Door Cover furnace filter slot cover Quality, economical furnace filters from United Filter Wide selection of HVAC, Furnace AC Filters Bag Filters, Rigid Box Filters and HEPA Filters furnace filter slot cover Search for a slot about one inch wide with a hinged cover or removable cover Where to Find Air Filters in Different Types of HVAC Systems

aadhaar update online slot booking I think I'll make a similar cover for my furnace filter slot I see the potential for better return air flow upstairs by restricting leakage