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