Detailed Product Description all stainless steel pressure gauge without liquidSpecifications:Case sizes: 2.5, 4 inchesCase material: 304 ssBezel material: 304 ss bezel and bayonetTube and socket: 316ssConnection: 1/4, 3/8 and 1/2-inch NPT, BSP and PTType: bottom, back and front flangeScale range: -1 to 0 to 600 barsWindow (lens) material: acrylic, pcor glass is for optionAccuracy: 1.0, 1.6