A double-rod ram (1), preferably for an extruder, comprising an outer cylinder (10), an inner cylinder (20) installed therein and arranged concentrically therewith, a double-acting work piston (41) provided in the inner cylinder to be displaceable and a bypass device (50) with at least one bypass valve (52), wherein the work piston (41) divides the inner cylinder (20) into two compartments (42) and can be loaded with a hydraulic fluid from both compartments (42), wherein the bypass device (50) is so arranged that in a bypass position of the bypass valve (52) a fluid connection between the two compartments (42) is formed by a direct connection, preferably at least one bypass line, and in a work position of the bypass valve (52) no such fluid connection is present.