An adjustable connecting bar for releasable fastening of a child restraint system to a vehicle seat having a mounted anchoring member, the connecting bar comprising a first elongated bar member and a second elongated bar telescopically interconnected and arranged for relative displacement along a longitudinal axis between a retracted end position and an extended end position of the connecting bar, the first elongated bar member being provided with a coupling device at an end thereof, the coupling device comprising a movable coupling member for engaging the anchoring member, the coupling device being transformable between a locked configuration and a release configuration, the coupling device comprising a displaceable latch member biased to engagement with the movable coupling member to latch the movable coupling member in the locked configuration, the coupling device being transformable from said locked configuration to said release configuration in a first operation step by means of a manually operable actuator operatively connected via a maneuvering system to the displaceable latch member for selectively disengaging the displaceable latch member from the movable coupling member, said connecting bar comprises a latch system (10, 11) housed within the connecting bar for selectively preventing extension and retraction of the connecting bar, the latch system comprising a first latch and a second latch, said first latch being operatively connected via the maneuvering system to the displaceable latch member, said first latch being arranged to lock said connecting bar in said extended end position and to prevent retraction of said connecting bar when said connecting bar is in said extended end position and said coupling device is in said release configuration, and said first latch being arranged to allow retraction of said connecting bar when said coupling device is in said locked configuration, said second latch being arranged to be transferrable from an active state to an inactive state, said second latch being arranged to in said active state prevent extension and to allow retraction of said connecting bar, and said second latch being arranged to in said inactive state allow both extension and retraction of said connecting bar, characterized in that said second latch is biased to the active state and transferrable from the active state to the inactive state in a second operation step by means of the manually operable actuator, the second operation step being separate from the first operation step and only allowed when the coupling device is in the release configuration, and the second latch being arranged to return to the active state upon release of the manually operable actuator. the coupling device comprising a movable coupling member for engaging the anchoring member, the coupling device being transformable between a locked configuration and a release configuration, the coupling device comprising a displaceable latch member biased to engagement with the movable coupling member to latch the movable coupling member in the locked configuration, the coupling device being transformable from said locked configuration to said release configuration in a first operation step by means of a manually operable actuator operatively connected via a maneuvering system to the displaceable latch member for selectively disengaging the displaceable latch member from the movable coupling member, said connecting bar comprises a latch system (10, 11) housed within the connecting bar for selectively preventing extension and retraction of the connecting bar, the latch system comprising a first latch and a second latch, said first latch being operatively connected via the maneuvering system to the displaceable latch member, said first latch being arranged to lock said connecting bar in said extended end position and to prevent retraction of said connecting bar when said connecting bar is in said extended end position and said coupling device is in said release configuration, and said first latch being arranged to allow retraction of said connecting bar when said coupling device is in said locked configuration, said second latch being arranged to be transferrable from an active state to an inactive state, said second latch being arranged to in said active state prevent extension and to allow retraction of said connecting bar, and said second latch being arranged to in said inactive state allow both extension and retraction of said connecting bar, characterized in that said second latch is biased to the active state and transferrable from the active state to the inactive state in a second operation step by means of the manually operable actuator, the second operation step being separate from the first operation step and only allowed when the coupling device is in the release configuration, and the second latch being arranged to return to the active state upon release of the manually operable actuator.