Analog Manometer Pressure Range -4 to 4 in wc For Tubing Diameter 0.187 in Maximum Operating Pressure 100 psi Maximum Pressure 4 in wc Minimum Pressure -4 in wc Scale Units in wc Series 1221 Manometer Type Flexible U-Tube Housing Material Plastic Includes Gas Pressure Kit No Fluid Color Red Includes 1 oz Bottle Red Gage Fluid Carrying Plugs Vinyl Tube Connectors Lens Material Butyrate Minor Graduations 0.1 in wc Slack Tube Length 8 in Fluid Composition Petroleum Distillates