This air test assembly gauge is used in commercial, residential, and institutional HVAC applications. It consists of a 3/4 In. FPT chrome plated brass manifold, steel case, Kostil Polymer window, 3/4 In. FPT x Schrader type air valve with cap connection, and copper alloy Bourdon tube pressure element. Accuracy is ASME, Type B. Pressure rating scale is 0 to 30 psi.