Danfoss AB-QM 4.0 CO⁶ Flexo (003Z1581) — a prefabricated DN 15 pressure-independent balancing and control valve (PICV) assembly for terminal heating/cooling connection. The integral differential-pressure controller holds the flow through the settable orifice constant regardless of pressure fluctuations in the network, so each terminal delivers its design flow without manual re-balancing. Connection: 18 mm press fitting. normal flow range, nominal flow 0.7 m³/h. Pressure class PN 16, media temperature 0 °C to 90 °C (media). OEM designation "AB-QM 4.0 CO6 Flexo DN15 18 mm". OEM P/N 003Z1581. EAN 5715162731963. Technical data quoted verbatim from store.danfoss.com (code 003Z1581).