"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. Connection Size in. 1/4 Male NPT, Accuracy ASME/ANSI B40.1 Grade A 2-1-2, Bourdon Tube C-shaped, Fill Material Glycerin, Pointer Black enameled aluminum, Max. PSI 1,000, Gauge Diameter in. 2 1/2, Mount Type Back, Range PSI 0-1,000, Dial White aluminum, Recommended Use Air, gas, oil, water, Window Material Temperature compensating polycarbonate, Movement Brass."