This document provides connectors such as a connector for enabling fluid transfer between a first fluid container and a second fluid container, which connector comprises a first component that is arranged to be connected to a first fluid container and a second component that is arranged to be connected to a second fluid container. The first component can be non-rotatably connected to the second component before a second fluid container is connected to the second component and/or before a first fluid container is connected to the first component. The connector can comprise a locking and rotation-enabling element that is arranged to be activated once a second fluid container has been connected to the second component, and/or once a first fluid container has been connected to the first component, which locking and rotation-enabling element enables the first component and the second component to rotate freely with respect to one another.
