A method for packing a chromatography column assembly with chromatography media, comprising the steps of: providing: a column tube comprising a basic column wall and an extension tube wall, the basic column wall having a closed first end comprising an inlet/outlet, the extension tube wall including a media inlet adjacent a second end of the column tube, wherein the basic column wall and the extension tube wall have essentially the same inner diameters and connected they form the column tube; and an adaptor positioned inside the column tube initially at a first position between the second end of the column tube and the media inlet, the adaptor being arranged to be moved along the inner surface of the column tube in sliding and sealing contact with an inner face of the column tube, the column tube and adaptor arranged initially such that they define an internal volume and such that the media inlet is in fluid connection with the internal volume; connecting a media slurry source to the media inlet; at least partially filling the internal volume with media slurry via the media inlet; forcing the adaptor to move along the inner surface of the column tube from the second end towards the first end of the column tube to a second position to reduce the internal volume such that the media inlet is no longer in fluid connection with the reduced internal volume, wherein said second position corresponds to a final position of the adaptor, the invention being characterized in by the steps of: after forcing the adaptor to the second position beyond a height position of the media inlet and the extension tube wall, securing the adaptor in said second position to the basic column wall, separating from the tube the extension tube wall left above the adaptor, from the rest of the column, and providing the system and the media slurry as pre-sterilized and providing aseptic and/or sanitary connectors to the media inlet, the first end inlet/outlet and/or the adaptor inlet/outlet. providing: a column tube comprising a basic column wall and an extension tube wall, the basic column wall having a closed first end comprising an inlet/outlet, the extension tube wall including a media inlet adjacent a second end of the column tube, wherein the basic column wall and the extension tube wall have essentially the same inner diameters and connected they form the column tube; and an adaptor positioned inside the column tube initially at a first position between the second end of the column tube and the media inlet, the adaptor being arranged to be moved along the inner surface of the column tube in sliding and sealing contact with an inner face of the column tube, the column tube and adaptor arranged initially such that they define an internal volume and such that the media inlet is in fluid connection with the internal volume; a column tube comprising a basic column wall and an extension tube wall, the basic column wall having a closed first end comprising an inlet/outlet, the extension tube wall including a media inlet adjacent a second end of the column tube, wherein the basic column wall and the extension tube wall have essentially the same inner diameters and connected they form the column tube; and an adaptor positioned inside the column tube initially at a first position between the second end of the column tube and the media inlet, the adaptor being arranged to be moved along the inner surface of the column tube in sliding and sealing contact with an inner face of the column tube, the column tube and adaptor arranged initially such that they define an internal volume and such that the media inlet is in fluid connection with the internal volume; connecting a media slurry source to the media inlet; at least partially filling the internal volume with media slurry via the media inlet; forcing the adaptor to move along the inner surface of the column tube from the second end towards the first end of the column tube to a second position to reduce the internal volume such that the media inlet is no longer in fluid connection with the reduced internal volume, wherein said second position corresponds to a final position of the adaptor, after forcing the adaptor to the second position beyond a height position of the media inlet and the extension tube wall, securing the adaptor in said second position to the basic column wall, separating from the tube the extension tube wall left above the adaptor, from the rest of the column, and providing the system and the media slurry as pre-sterilized and providing aseptic and/or sanitary connectors to the media inlet, the first end inlet/outlet and/or the adaptor inlet/outlet.