A fluid path set for delivery of an injection fluid, comprising: a first flexible tube having a length defined between a first end portion and a second end portion thereof when straightened and having a longitudinal axis (L 1 ) extending along the length thereof, a second flexible tube having a length defined between a first end portion and a second end portion thereof when straightened and having a longitudinal axis (L 2 ) extending the length thereof, the first flexible tube and the second flexible tube each defining a transverse formation extending generally perpendicular to the longitudinal axis corresponding thereto; and a clip mechanism maintaining the transverse formation in each of the first flexible tube and the second flexible tube , comprising a clip body comprising opposing flanges , each opposing flange defining at least a pair of recesses , each of the pair of recesses receiving one of the first flexible tube and the second flexible tube , respectively, to define the respective transverse formations , and a separating support section connecting the opposing flanges such that the clip mechanism extends across the transverse formations , namely a loop, and maintains a configuration of the respective transverse formations ; whereby the clip mechanism is arranged between each first end portion and each second end portion; whereby, due to the respective transverse formations , a fluid contained within either of the first flexible tube and the second flexible tube at one end portion thereof cannot flow through the length of the first flexible tube or the second flexible tube to displace a less dense fluid contained within the first flexible tube or the second flexible tube at the other end portion thereof under gravitational flow. a first flexible tube having a length defined between a first end portion and a second end portion thereof when straightened and having a longitudinal axis (L 1 ) extending along the length thereof, a second flexible tube having a length defined between a first end portion and a second end portion thereof when straightened and having a longitudinal axis (L 2 ) extending the length thereof, the first flexible tube and the second flexible tube each defining a transverse formation extending generally perpendicular to the longitudinal axis corresponding thereto; and a clip mechanism maintaining the transverse formation in each of the first flexible tube and the second flexible tube , comprising a clip body comprising opposing flanges , each opposing flange defining at least a pair of recesses , each of the pair of recesses receiving one of the first flexible tube and the second flexible tube , respectively, to define the respective transverse formations , and a separating support section connecting the opposing flanges such that the clip mechanism extends across the transverse formations , namely a loop, and maintains a configuration of the respective transverse formations ; whereby the clip mechanism is arranged between each first end portion and each second end portion; whereby, due to the respective transverse formations , a fluid contained within either of the first flexible tube and the second flexible tube at one end portion thereof cannot flow through the length of the first flexible tube or the second flexible tube to displace a less dense fluid contained within the first flexible tube or the second flexible tube at the other end portion thereof under gravitational flow. <EOS>