Danfoss AB-QM 4.0 Flexo with AB-QM valve, 3-way ball valve design, and 80mm center distance is a compact and time-saving connection set. It’s designed to create optimal hydronic balance in cooling and heating applications with variable flow (such as fan coil units (FCU) or chilled beams).Flow is controlled by the AB-QM pressure-independent control valve to avoid overflow and reduce the efficiency of the thermal unit.