Abstract: An electronic assembly having a multi-slot card assembly and a chassis is provided. The chassis has two or more chassis mounting slots, each including three walls. The multi-slot card assembly is mountable into the chassis and has two or more protrusions. The card assembly comprises at least one heat frame, at least one circuit card module mounted to the at least one heat frame, and at least one expandable fastener. When the card assembly is mounted into the chassis and the at least one fastener is expanded, the at least one fastener applies force against both of one of the walls of the slot and a surface of the at least one heat frame.