Breather Desiccators combine a humidity indicator plug and tubular body to create a single free breathing unit. Air enters the unit via a Polytetrafluoroethylene (PTFE) coated wire mesh to prevent ingress of dust and other small containments. The inlet is also protected by a weather shield for added protection.
Air entering the unit due to pressure differentials from atmospheric or altitude changes is dried to ensure the internal humidity remains low. If the pressure differential is reversed, the direction of the airflow is also reversed until pressure equalization is achieved.
This style of desiccator is commonly used on airborne equipment.