The ceiling plate or grease shield protects the stirrer above from contamination from food debris. The stirrer cover fits into the top of the microwave. Buffalo GK640, Buffalo GK641 cooling fan assembly - DE31-10180A.
Buffalo FB865 commercial microwave ceramic base plate - ANE010T8U0AP - FITS FB86
Panasonic NE-1757 spatter shield (stirrer cover)
Panasonic NE-1843, Panasonic NE-1853 spatter shield (stirrer cover) - H2011-3280
Panasonic NE-1846, Panasonic NE-1856 spatter shield (stirrer cover)
Panasonic NE-1780, Panasonic NE-1880 spatter shield (stirrer cover) - A20113030G
Panasonic NE-1815 & NE-1878 spatter shield (stirrer cover) - H2011-3B10S
