Easy to install, this return air grille features all-steel construction and includes all screws needed for mounting. The grille opens from the front, making it quick and easy to replace filters. HVAC grilles and registers are not measured by the total size of the cover but by the size of the vents or grates. Most plates extend 1 to 1.5 inches beyond the vents. So, a 25" x 16" register will cover a 25" x 16" vent area on a roughly 28" x 19" plate.