Original For Galanz 2M319J 1KW Universal M24FB-610A Cavity Magnetron Microwave. Original M24FA-410A Magnetron Module Microwave Oven Parts Heating Tube Replace. In the microwave oven, the role of mica is to let the microwave into the microwave oven, block the microwave emitting hair smoke and other pollution, to prevent reducing the efficiency of the microwave oven!