The purpose of a microwave wave guard cover is to shield the opening through which the microwaves enter the oven cavity.
Universal Microwave Wave Guide Premium Grade Mica Sheets 5" x 8" (Pack of 5)
Universal Microwave Wave Guide Cover Mica Splash Board 200x125mm Waveguide Sheet
Kenwood Microwave Wave Guide Cover Wall Guard Plate 117 x 65mm
CDA Microwave Wave Guide Cover VM201, VM231, VM451, VM551
Kenwood Microwave Wave Guide Cover K23CM13E K25CS14 K25MMS14 K30CSS14 K30CSS14E
Neff Microwave Wave Guide Cover Mica