Experience accuracy and reliability with the Dwyer Magnehelic Differential Pressure Gauge, designed to measure pressure variations from 0 to 150 mm of Water.  Maximum pressure is 15 PSIG. Engineered for precision, this gauge is a trusted instrument for both professional and hobbyist applications, offering a clear and easy-to-read display. Crafted in the United States, this single-unit gauge is suitable for back mount configurations and is built to withstand the rigorous demands of everyday use. The durable construction paired with the renowned Dwyer brand quality ensures long-lasting performance and steadfast measurement.
I PURCHASED THIS GAUGE USED AND I DO NOT KNOW MUCH ABOUT IT OTHER THAN THE FACT THAT THE THE NEEDLE MOVES IN RESPONSE TO AIR PRESSURE APPLIED TO EITHER THE HIGH PRESSURE OR LOW PRESSURE PORTS.  THE NEEDLE WILL MOVE FROM IT'S CURRENT POSITION OF 2 DOWN TO 0 AND UP TO 15 WHEN AIR PRESSURE IS APPLIED TO ONE OF THE TWO PORTS.  THIS ITEM IS NOT RETURNABLE.  YOU ARE PUCHASING THE GAUGE AS SHOWN IN THE PHOTOS AND NOTHING ELSE.