The E41 is suitable for installation in domestic water supply lines (after the meter) in systems where inlet pressures do not exceed 300 psi and where system temperatures do not exceed 180 deg F. The E41 is set at 45 psi and comes with an adjustable spring range of 20-70 psi. Low pressure (10-40 psi) and high pressure (71-150 psi) settings are also available.