A connector assembly for making fluid connections comprising: a first hollow connector body and a second hollow connector body, each body having first and second ends (105, 106), an exterior and an interior which extends between the first and second ends (105, 106); a coupling mechanism arranged to couple the first and second connector bodies (101, 102) at the first ends of the bodies; a hollow piston having first and second ends (141, 142) and an interior extending between the first and second ends, the piston being movable from a first position, wherein the piston is movably located in the interior of the first connector body, to a second position, wherein the piston bridges and seals against the interiors of the first and second connector bodies (101, 102) and the first end of the piston is located between the first and second ends (105, 106) of the second connector body; and a rotatable actuator mounted around the exterior of at least one of the first and second connector bodies (101, 102) and coupled to the piston to move the piston from the first position to the second position in response to rotation of the actuator, characterized in that in the first position of the piston the first and second ends (141, 142) of the piston are located between the first and second ends (105, 106) of the first connector body, in that in the second position of the piston the second end of the piston is located between the first and second ends (105, 106) of the first connector body, and in that the interior of the piston fluidly communicates between the second ends of the first and second connector bodies (101, 102). a first hollow connector body and a second hollow connector body, each body having first and second ends (105, 106), an exterior and an interior which extends between the first and second ends (105, 106); a coupling mechanism arranged to couple the first and second connector bodies (101, 102) at the first ends of the bodies; a hollow piston having first and second ends (141, 142) and an interior extending between the first and second ends, the piston being movable from a first position, wherein the piston is movably located in the interior of the first connector body, to a second position, wherein the piston bridges and seals against the interiors of the first and second connector bodies (101, 102) and the first end of the piston is located between the first and second ends (105, 106) of the second connector body; and a rotatable actuator mounted around the exterior of at least one of the first and second connector bodies (101, 102) and coupled to the piston to move the piston from the first position to the second position in response to rotation of the actuator, characterized in that in the first position of the piston the first and second ends (141, 142) of the piston are located between the first and second ends (105, 106) of the first connector body, in that in the second position of the piston the second end of the piston is located between the first and second ends (105, 106) of the first connector body, and in that the interior of the piston fluidly communicates between the second ends of the first and second connector bodies (101, 102).