The Glass Tray is an OEM part for GE microwaves. This tray sits on the turntable support and rotates to ensure even cooking and heating of food.   Common causes of a bad glass tray include accidental drops, cracks from overheating, or regular wear and tear over time.  Symptoms of a bad glass tray include: Visible cracks or chips in the tray The tray not rotating properly Uneven cooking or heating of food The tray wobbling or not sitting securely on the turntable support This OEM GE part is also compatible with Hotpoint, RCA, and some Kenmore models.WB27X43590 (AP7209961) replaces WB49X10166.