This assembly includes the damper door and frame.

This bracket holds the metal or plastic flapper that closes off the exhaust duct when the fan is not running and opens when the fan turns on. If the exhaust fan on your microwave does not appear to be working, the problem may be with the damper assembly. If the damper does not open and close easily, check for any damage to the bracket, and replace if it is damaged or faulty. This genuine OEM exhaust damper measures approximately 12 inches long by 5 inches wide.

This metal vent damper door closes off the exhaust duct when the fan is not running to stop outside air from entering the microwave unit, and opens when the fan turns on to allow air to vent away from the microwave. This vent damper door measures approximately 10 inches long x 3 inches wide and fits LG microwaves.