The Model HD18 18" Hinged Door Depth Extension Kit fits on the Model H318 structured wiring enclosure. The ventilated enclosure cover secures and protects the structured wiring components mounted inside the Model H318 enclosure. The hinged door increases the cabinet depth for larger power supplies and improved cooling. The white cover has a smoked plexiglas window. The optional Model H208 lock kit can be installed on the cover for additional security.