Product review (3 stars): GE microwave oven wave guide cover (mica sheet)
Arrived a day or two later than expected; packed in an envelop with corrugated cardboard protection, which was bent in two places.  The wave guide (same as micro wave oven brand name) was also bent, and did not cover the entire opening in the oven.  Mounting  holes matched up and was installed easily; my daughter will be sending for a replacement part.