The new OPW 19DEF-0500SS 3/4" NPT DEF Automatic Shut-Off Nozzle is used for dispensing of Diesel Exhaust Fluid (DEF) for on-road, off-road, commercial and industrial heavy-duty trucks, farming or other diesel powered vehicles. The Duratuff® lever guard not only provides for rugged durability when dropped but it won’t scratch your fleet vehicle.