"Brass movement with C shaped Bourdon 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. Movement Brass, Recommended Use Air, gas, oil, water, Connection Size in. 1/4 Male NPT, Max. PSI 3,000, Fill Material Glycerin, Dial White aluminum, Accuracy ASME/ANSI B40.1 Grade A 2-1-2, Pointer Black enameled aluminum, Range PSI 0-3,000, Window Material Temperature compensating polycarbonate, Mount Type Stem, Gauge Diameter in. 4, Bourdon Tube C-shaped."