The Plate Bottom is an OEM part for GE microwave ovens. It forms the base surface area that internal microwave components are securely mounted and attached to.  Causes of failure include warping and cracking of the metal shelf from prolonged exposure to high temperatures.   Symptoms of a bad plate bottom include: Visible distortions or cracks in the metal material   Loose mounting locations for interior assembly parts Air gaps impairing heat dissipation from components   Eventual failure of attached parts over long term use This OEM GE replacement is also compatible with Hotpoint, RCA and select Kenmore microwave models.WB07X32843 (AP6888455) replaces WB07X11225.