To determine the size of the required ventilation grill, it is best to remove the old grill and measure the height and width of the ventilation hole.
Choose a new ventilation grill at least 2 inches larger than the measured size and check the internal dimensions of the grill. An additional 2 inches will allow you to cover the edges of the ventilation holes and secure the grille.
Check the outer dimensions of the grille to ensure that they cover all elements around the ventilation hole.