Abstract: An improved combined flow metering and shut-off valve having inner and outer valve parts which are axially movable relative to one another to effect relative axial movement of a metering valve plug on one part into and out of a metering bore on the other for regulating or blocking flow through the valve flow passage. Through the use of an interlocking collar, the inner and outer valve parts can be moved with respect to each other through rotation of the collar by one hand which rotation varies the relative axial position between the valve parts to change the metering. A seal with spaced sealing lips is provided within the valve. The lips are spaced a distance sufficient to assure that their contact areas never overlap so that contamination cannot pass into fluid flowing through the valve, which fluid is usually being introduced into a living person.