The function of the ventilation cap is to ventilate, mainly to balance the internal and external air pressure of the reducer. Reducer outdoors or under the condition of continuous operation, the temperature will become very high and the inside of the reducer lubricating oil gasification into gas swells, of course, in order not to damage the oil seal or connection of the speed reducer, reducer shall be the highest level of congestion before use put on ventilation hat (also called a "vent plug"), guarantee the discharge reduction during the casing gas.

      Note: if the air cap of the reducer is not changed, it may cause oil leakage. Therefore, please replace the air cap as required before using the madler reducer.