Control ring (10; 210) for controlling the flow of a pressure medium in a displacement pump (200), said control ring (10; 210) is; €¢ centred about a rotational axis (ax) €¢ extending along said rotational axis (ax), €¢ having an inner and an outer diameter (d, D) and thereby an inner and outer radial surface (11, 12; 211, 212) €¢ a first and a second axial surface (13, 14; 213, 214), wherein said first axial surface (13; 213) having an interface section (20; 220) provided with at least a first and a second opening (21, 22; 221, 222), which first and second opening (21, 22; 221, 222) are separated by a first and a second intermediate section (15, 16; 215, 216), characterised in, that said first and second opening (21, 22; 221, 222) are mouthing to a corresponding mouthing area provided at either of the inner and outer radial surface (11, 12; 211, 212).