A first sheet metal is configured into an enclosure and first and second pluralities of fingers are bent inwardly from the sheet metal to serve retention fingers, the first plurality frictionally engaging the outside of a honeycomb material to retain it in the enclosure while the second plurality serve as a limit stop to keep the honeycomb above the electrical device being protected. The honeycomb may have two sets of oppositely angled honeycomb cells, one capturing airflow from a fan and drawing it into the enclosure which the second set permits convective air currents to rise upwardly out of the enclosure. Alternatively, the cells of the honeycomb may be vertical convective air currents will flow under the wall of the enclosure, with or without the aid of a fan, the vertically directed cells of the honeycomb creating a chimney effect to dissipate the heat.