Brass movement with C shaped Boudon tube. 1/4in. NPT male connection. For use with air, gas, oil or water. Black enameled aluminum pointer, white aluminum dial and temperature compensating polycarbonate window. Glycerin filled to dampen pulse and vibration. Accuracy ASME/ANSI B40.1 Grade A 2-1-2. Fill Material Glycerin, Pointer Black enameled aluminum, Recommended Use Air, gas, oil, water, Mount Type Back, Bourdon Tube C-shaped, Range PSI 0-1,000, Accuracy ASME/ANSI B40.1 Grade A 2-1-2, Connection Size in. 1/4 Male NPT, Gauge Diameter in. 2 1/2, Dial White Aluminum, Movement Brass, Window Material Temperature compensating polycarbonate.