A bottle connector for use in a medical fluid transfer arrangement, said bottle connector having an axial direction and a radial direction and comprising: a first generally cylindrical part having a first end and a second end, said first generally cylindrical part comprising a hollow piercing member comprising an inner channel; and a second generally cylindrical part connected to the first generally cylindrical part and concentrically arranged with respect to each other, the second generally cylindrical part having a first end and a second end, the second generally cylindrical part comprising a bottle coupling member, for coupling said bottle connector to a medical bottle, the second generally cylindrical part being configured to move between a transport configuration and a fluid transfer configuration, wherein the second generally cylindrical part comprises a locking tongue carrying a locking protrusion, wherein, when the second generally cylindrical part moves from the first configuration, corresponding to the transport configuration, to the second configuration, corresponding to the fluid transfer configuration, the second generally cylindrical part moves along a longitudinal axis without rotation, characterized in that: the first generally cylindrical part comprises a first locking opening and a second locking opening, wherein the locking protrusion is arranged to cooperate with the first and second locking openings for locking the bottle connector in the transport configuration and the fluid transfer configuration, respectively. a first generally cylindrical part having a first end and a second end, said first generally cylindrical part comprising a hollow piercing member comprising an inner channel; and a second generally cylindrical part connected to the first generally cylindrical part and concentrically arranged with respect to each other, the second generally cylindrical part having a first end and a second end, the second generally cylindrical part comprising a bottle coupling member, for coupling said bottle connector to a medical bottle, the second generally cylindrical part being configured to move between a transport configuration and a fluid transfer configuration, wherein the second generally cylindrical part comprises a locking tongue carrying a locking protrusion, wherein, when the second generally cylindrical part moves from the first configuration, corresponding to the transport configuration, to the second configuration, corresponding to the fluid transfer configuration, the second generally cylindrical part moves along a longitudinal axis without rotation, characterized in that: the first generally cylindrical part comprises a first locking opening and a second locking opening, wherein the locking protrusion is arranged to cooperate with the first and second locking openings for locking the bottle connector in the transport configuration and the fluid transfer configuration, respectively. the first generally cylindrical part comprises a first locking opening and a second locking opening, wherein the locking protrusion is arranged to cooperate with the first and second locking openings for locking the bottle connector in the transport configuration and the fluid transfer configuration, respectively.