The flowmeter connection for the wall mount consists of a swivel barb, in order to easily orientate in the required direction. This can be connected to an existing hose or an added hose made to length with a chosen vacuum source connector. The F/Air cannister will self-thread to the end of the unit, holding it in place.
Note: The flowmeter connection for Round Pole Mount consists of a 45 degree chrome elbow with a 1/4"ID chrome hose barb, which can be connected to an existing hose or an added hose made to length with a chosen Vacuum Source connector.
Looks like you haven't made a choice yet.