Air vent gland Air vent gland In order to choose the right ventilation plug unit (pressure balance elements) for a specific application, the working principles of the unit must be known first. Ventilation plugs are permeable to "gases and vapours, e.g. air" but impermeable to "liquids and dust, e.g. water". The permeability resistance to liquids depends on the pore size and structure of the membrane inside these devices. To conclude, the ventilation plug can reduce and even fully eliminate the adverse effects of humidity in the environment. Water drops on the bottom of the enclosure are normal,but the inherent damage becomes insignificant due to the existence of a ventilation plug. Dimensions(mm) Recom.Hole Diam(mm) Protection degree air vent gland type Thread size Model And Size Processing Size Ventilation Fan Size Product Characteristics 1.It is easy to exhaust heat of inside box to outside. 2.It is easy to install cooling pan inside the box. 3.It is designed to prevent the penetration of rain.