McMaster 8631T24 Breather Vent Nylon Plastic, 3/4 NPT Male

Protect against excess vacuum and pressure in cylinders, gear boxes, enclosures, manifolds, and tanks. You can also use these breather vents to block debris from entering equipment.

Breather vents with splash guard are good for containers that are often filled and drained; they have a guard that prevents oil from splashing out of the vent hole.