The Damper is an OEM component for LG microwaves. Located within the cooking cavity, it regulates airflow and safely vents steam escaping heated foods.  Causes of a faulty damper can involve standard wear and exposure accepting steam and condensation release. Food or liquid particles drying within tracks also threaten eventual adhesion issues restricting travel if left unaddressed between cleanings. Symptoms of a damaged or defective damper include: Inability to adequately vent excess moisture from heating   Potential messes spilling beyond the microwave frame   Grating sounds or squeaks emitting during cooking Flaps possibly stuck inhibiting steam circulation  This damper is also compatible with Kenmore microwaves as well.4900W1A001B (AP4438572) replaces 1266826, 3B71432A, AH3524148, EA3524148, PS3524148.