Switch enclosures may also be required to be weatherproof, corrosion resistant, or submersible. Both are printed on rip-resistant and weatherproof paper. For outdoor units some form of weatherproof lid and additional sealing around joints is provided. It has double bonded laminated float glass for windows that are crystal-quality, weatherproof, and unbreakable. It tightens and stiffens fabric stretched over airframes, which renders them airtight and weatherproof. A weatherproof outdoor model was announced in September 2017. The UHF connector is not weatherproof. It is weatherproof without being overly bulky. The Mark XX mount was fully enclosed and supposedly weatherproof; in service, crews found otherwise. The Argentine base "Corbeta Uruguay" was closed and the buildings sealed to make them weatherproof. To weatherproof the structure, the external facade was rendered. Being weatherproof, the cupola was better suited to the wetter climates of northern Europe. On final closure, they slightly drop down to create a weatherproof seal. For areas of exposure, weatherproof paint must be used. DOD Unit loads generally use pallets, are less than , weatherproof, and stack high.