The Wave Guide Cover is an OEM part for Frigidaire microwaves. The cover prevents food particles and moisture from entering the wave guide, helping to maintain the efficiency and safety of the microwave. Causes of a bad wave guide cover can include exposure to high heat, splatters from food and liquids, or regular wear and tear.  Symptoms of a bad wave guide cover include: Sparks or arcing inside the microwave Uneven cooking or heating Visible burns, cracks, or discoloration on the cover Noise or rattling sounds during operation This OEM Frigidaire part is also compatible with Electrolux, Gibson, Kelvinator and some Kenmore models.5304509435 (AP6230590) replaces 5304464061, 4546262, PS12071278.