As a reference dimension; the overall diameter of the top cap flange = 43mm.
This is how the filter sits in the tank. Note how little of the tank contents you can see and hence the non-standard, annoy the purists, but highly functional oil sight tube.
This is how the filter sits in the tank. Note how little of the tank contents you can see and hence the non-standard, annoy the purists, but highly functional oil sight tube.