When old damp or contaminated can react to microwaves by arcing. Fits Models: NN-E299SM, NN-E229BB NN-E279WM, NN-E289BM, NN-K18JM, NN-K179WB NN-K189MB, NN-E281MMB, NN-E271WB, NN-E209WB, NN-K181MM, NN-271WM, NN-281BM, NN-E27JW, NN-E28JM, NN-E28JB, NN-S29KSM, NN-E27JWM.
eBay