Abstract: According to an illustrative example of the invention, a chair column comprises a lockable gas spring for height adjustment of the chair column. The gas spring is inserted into a stand tube of the chair column. The piston rod extends downwards and is rotatably fastened to a bottom part of the stand tube. The cylinder of the gas spring extends upwards out of the upper end of the stand tube. At the upper end of the cylinder there is provided in axial alignment with the axis of the cylinder a valve pin. A pushing member acts onto the valve pin. The pushing member is connected with a Bowden cable. One end of the Bowden cable core is fastened to a guide sleeve of the pushing member. The tube member of the Bowden cable acts onto the pushing member. The other end of the Bowden cable is connected to a releasing lever by which the valve can be opened. When the valve is opened, the working chambers located on both sides of a piston are interconnected so that height adjustment of the gas spring is possible.