Abstract: A combined steel oil control ring is provided which has steel side rails and a steel spacer expander. The spacer expander includes ear portions for contacting the side rails. The ear portions are substantially equally spaced with respect to each other along the internal circumferential portion of the spacer expander. The ear portions have radially external circumferential surfaces adapted to press the side rails radially outwardly by using the resilient force caused by the spacer expander. The spacer expander has up-and-down contours formed circumferentially along the radially external circumferential surface, for preventing the side rails from circumferentially rotating relatively to the spacer expander. The up-and-down contours each include at least two axially extending groove regions and at least three axially extending flat regions. The groove regions and flat regions are dimensioned to extend the life span of the contours and the dies.