The Tru-Flate Air Line Gauge Polycarbonate 1-4 in. NPT 24-804 is a professional and accurate pressure gauge, perfect for air, water, oil and other compatible fluids. It offers a shatterproof crystal, a pressed steel case, brass fitting, and dual markings. The nominal accuracy of the gauge is 3-2-3%, with +/- 3% in top and bottom third and +/- 2% in the middle third. The gauge also has a back mount, brass 1/4-18 male NPT fitting and a 0-300 PSI range.