1800 Series low-pressure models have a maximum inlet pressure of 150 psi and offer outlet pressures ranging from 3.5" w.c. to 5 psi. 2000 Series high pressure models allow a maximum inlet pressure of 150 psi and outlet pressures ranging from .5 psi to 15 psi. The 1800 Series can be ordered as Full Relief, Partial Relief or No Relief Regulator. 2000 Series Regulators are non-relieving. Both models are available with Overpressure Shutoff, Underpressure Shutoff and monitor capabilities.