The low pressure gauge adopt capsule or bellow as the sensitivity part, can measure the micro-pressure or negative pressure of the gassed that have no corrosion function to the copper alloys and have no explosion. And it is widely used in boiler ventilation, gas tube and fuel setting and so on. l. Accuracy class: 2.5%, 1.6% 2. Connection thread: 1/8", 1/4", 1/2", 3/8"inches BSP, BSPT, NPT or according to customers' requirements 3. Case material: steel, plastic, stainless steel. 4. Dial size: 1 1/2", 2", 2 1/2", 3", 4", 6" 5. Window materials: glass, polycarbonatel. 6. Ranges: 0-25mbar to 0-1000mbar and vacuuml 7. Can be filled with dampening liquidl 8. Protection degree: IP55-IP67l 9. Connector and movement parts: brass/phosphor bronze or AISI316L, SUS304