With the help of our pneumatic Posimat, the roof unit is taken out of a storage container and moved almost weightlessly into a transfer position. In this position it is docked onto the mounting manipulator which moves it to the mounting line where the roof unit is inserted through the wind shield opening into the vehicle interior. A gripper positions the unit inside the roof opening where it is screwed in place. Then the device is lowered and moved out through the wind shield opening, back into the transfer position. The device can easily be swiched to mount a variety of different roof units.