4" flanged zero governor 5 psi max regulator. 210 Series balanced valve design regulators are lockup-type regulators. Their balanced valve design allows them to maintain steady outlet pressure control with varying inlet pressure. As a result, the 210 Series provides precise regulation over a wide range of pressures and flow rates. Applications include gas-fired boilers, steam generators, industrial furnaces, and ovens. In addition, a remote sensing option is available on 210D, E, and G models. Suitable for natural, manufactured, mixed gases, liquefied petroleum gases, LP gas-air mixtures, and DIN EN 437 gas families 1, 2, and 3.