Dwyer Instruments, Inc. 2001 Series 2000 Magnehelic&reg; Differential Pressure Gage Temperature Limits: 20 to 140F.*(-6.67 to 60C). Service: Air and non-combustible, compatible gases. (Natural Gas option available.) Pressure Limits: -20 in Hg. to 15 psig; 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.