"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. NOTE Image shown is representative of the guage style, not necessarily identical to what will be received. Window Material Temperature compensating polycarbonate, Dial White aluminum, Gauge Diameter in. 2 1/2, Pointer Black enameled aluminum, Fill Material Glycerin, Movement Brass, Recommended Use Air, gas, oil, water, Connection Size in. 1/4 Male NPT, Range PSI 0-3,000, Bourdon Tube C-shaped, Max. PSI 3,000, Mount Type Back, Accuracy ASME/ANSI B40.1 Grade A 2-1-2."