MANUFACTURER DIRECTService: Air and non-combustible, compatible gases. (Natural Gas option available.)Pressure Limits: -20 in Hg. to 15 psig; Temperature Limits: 20 to 140°F. (-6.67 to 60°C).Mounting Orientation: Diaphragm in vertical position. Consult factory for other position orientations.Process Connections: 1/8" female NPT duplicate high and low pressure taps - one pair side and one pair back.2003, Dwyer Instruments, Inc., 0-3.0 Magnehelic Diff. Pressure Gauge