An apparatus and system for transferring a liquid, such as a liquid anesthetic, from a reservoir to a machine while minimizing the release of the liquid to the surrounding environment. The apparatus can include a first component having a through-hole, and a second component having an aperture, a support member extending into the aperture having a protrusion configured to be capable of sealing the through-hole, wherein a fluid in the reservoir may exit the reservoir by way of the through-hole and the aperture, wherein twisting the first component and second component relative to each other causes the protrusion to seal or unseal the through-hole thereby allowing or preventing the flow of fluid. A portion of the exterior surface of the second component can have a polygonal shape.
