Danfoss AB-QM ANSI 2" — pressure-independent balancing and control valve (PICV) for a external thread NPT connection. A single AB-QM valve combines three functions in one body: an automatic flow limiter that holds the set flow constant regardless of pressure fluctuations elsewhere in the system, a control valve (operated by a Danfoss thermal or modulating actuator on the M30 x 1.5 connection), and a manual shut-off. Presetting fixes the maximum flow so the branch is inherently balanced — no manual balancing valve or commissioning flow-measurement is required. Ductile iron (EN-GJL-250) body,, 55 gal/min nominal flow, 4 psi to 60 psi control differential, stroke 10 mm, media temperature 15 °F to 250 °F, supplied with test plugs. OEM P/N 003Z0781. EAN 5710104034669. Technical data quoted verbatim from store.danfoss.com (code 003Z0781).