Abstract: The invention is a retainer assembly that, upon being attached to a panel and placed in a slot in a housing, provides a smooth and continuous surface that allows the panel to slide freely in and out of the housing. The panel can be firmly retained within the housing slot by expanding the width of the retainer assembly. The retainer assembly provides a more uniform heat transfer surface when abutted against the housing slot. The retainer assembly is self-contained to prevent the individual components from becoming dispersed if the assembly is damaged or disassembled. Additionally, retainer assembly provides a mechanism to prevent it from accidentally disassembling.