Fluid regulators provide a fluid to a cannula for use by a person. Fluid conservers also a fluid to a cannula for use by a person. A fluid conserver may be operational in a continuous flow mode of operation and an intermittent flow mode of operation. The selection of either the continuous flow mode of operation and the intermittent flow mode of operation may be based on a position of a flow selector. A home fill device may operate with a fluid conserver and may include an oxygen concentrator which provides a source of fluid.