The present invention relates to a spacer tube (1) for the production of spacer frames for multi-pane insulated glazing having at least two glass panes, having a tube wall (2) that has a visible wall (6), a bottom wall (7) that lies opposite the former, and two side walls (8) that lie opposite one another, for a connection with a glass pane each, whereby at least one of the two side walls (8) is cold-strengthened, at least in partial regions, to increase the bending stiffness of the spacer tube (1), as well as a multi-pane insulated glazing having a spacer frame having at least one such spacer tube (1), and a device and a method for production of the spacer tube (1).