The Door Mullion is an OEM part for GE refrigerators. It is a vertical component that separates the fresh food and freezer compartments, while allowing for the seal and closure of the refrigerator doors. Causes of a bad door mullion may include physical damage from impact or mishandling, wear and tear over time, or compatibility issues with the specific refrigerator model. Symptoms that may indicate a need to replace the door mullion include: Air leaks or drafts between the fresh food and freezer compartments Difficulty in closing or sealing the refrigerator doors properly Visible cracks, breaks, or damage to the mullion itself Condensation or frost buildup around the mullion area This GE replacement part is also compatible with Hotpoint, RCA, and some Kenmore refrigerator models.WR17X12591 (AP4363643) replaces 1477374, AH2340319, EA2340319, PS2340319, WR17X12596.