Automotive manufacturers must test individual parts and components for heat resistance before mass production. Determining resistance and behavior in different climatic regions, including humid and dry heat, plays a major role. Open-air sites in Florida, Arizona, South Africa and other hot regions are used for this purpose. The test boxes offer the advantage that individual parts can be tested at a very early stage, before the entire vehicle is ready for testing. The test box is used universally for endurance testing of a wide range of individual parts and components in the open air.