3/4 NPT (G 3/4) Copper Filter Breather
Breathing apparatus, also known as “the oil plug”, is the accessories for hydraulic power units plastic fuel tanks or steel tanks, the breathing apparatus to strengthen-and copper filter, preventing oil spills, oil directions.
Breather for plastic hydraulic reservoir tanks ,and also can be used for metal oil tank .
Here is the standard breatehr ,with indication of oil height ,with copper filter.
With copper filter inside