A screw on Air Breather manufactured by Parker Hannifin.
Ideally suited for use with static water and fuel tanks. Can also be used with mobile water tanks for window cleaning and car valeting. This breather can be used where it is not practical to run an external vent in a vehicle.
Dimensions:
Outside Diameter: 102mm
Height: 80mm (90mm when screwed into a Tek Tanks 1/2″ BSP female threaded socket)
Thread: 1/2″ BSP male.