The Mullion (White) is an OEM part for GE refrigerators. This is the vertical strip that helps seal the space between the French doors, ensuring an airtight closure when the doors are shut.  Causes of a bad mullion can include physical damage from impacts, wear and tear from regular use, or issues with the pivot or hinge mechanisms that allow it to fold and seal properly.   Symptoms of a bad mullion include: Doors not closing properly Visible gaps between the French doors Increased condensation or frost buildup around the door edges Higher energy consumption due to inefficient sealing This OEM GE part is also compatible with Hotpoint, RCA, and some Kenmore models.WR02X12818 (AP4510470) replaces 1567571, AH2374566, EA2374566, PS2374566.