An assembly having a source bottle and a refillable dispenser, the source bottle having a body and a threaded neck formed of one-piece, the refillable dispenser having a dispensing head and a filling and venting system, the refillable dispenser having a reservoir, The refillable dispenser has a threaded sleeve that can be screwed onto the threaded neck, thereby enabling the filling and venting system to be connected to the body, so that the fluid product in the source bottle can gravitationally flow from the source bottle into the reservoir through the filling and venting system, while the air from the reservoir can simultaneously flow from the reservoir into the source bottle through the filling and venting system.