Dual scaleBezel provides flange for flush mounting in panelClear plastic face is highly resistant to breakage and provides undistorted viewing of pointer and scalePrecision litho-printed scale is accurate and easy to readRed tipped pointer of heat treated aluminum tubing is easy to seePointer stops of molded rubber prevent pointer over-travel without damage"Wishbone" assembly provides mounting for helix, helix bearings and pointer shaftJeweled bearings are shock-resistant mounted to provide virtually friction-free motion for helix, and are motion damped with high viscosity silicone fluidZero adjustment screw is conveniently located in the plastic cover, and is accessible without removing the cover, while O-ring seal provides pressure tightnessHelix, mounted in jeweled bearings, is precision made from an alloy of high magnetic permeability and turns freely, following the magnetic field to move the pointer across the scaleCalibrated range spring is flat spring steel and small amplitude of motion assures consistency and long lifeSilicone rubber diaphragm with integrally molded O-ring is supported by front and rear plates and diaphragm motion is restricted to prevent damage due to overpressuresDie cast aluminum case is precision made and iridite-dipped to withstand 168 hour salt spray corrosion test, and the exterior is finished in baked dark gray hammerloidSamarium cobalt magnet mounted at one end of range spring rotates helix without mechanical linkagesApplications include filter monitoring, air velocity with Dwyer pitot tube, blower vacuum monitoring, fan pressure indication, clean room positive pressure indication, and duct, room, or building pressures