Description The Model 425 Wing Union Pressure Transmitters are rugged sensors designed for use with 1502 wing unions in demanding land-based and off-shore applications. The isolated, pressure sensing diaphragm minimizes zero-shift during hammer-up and eliminates long-term, signal drift in the field. The sensor diaphragm and wing union fitting are machined as one part. The Model 425 is constructed as an all-welded assembly using a deep penetration, proprietary, electron beam welding process, which also ensures hermetic integrity for all field conditions. These transmitters incorporate special assembly processes to vibration and shockproof the components to ensure performance are maintained during the rigors of fracturing and cementing applications. The 1502 wing union compatible fittings are machined of Inconel® X-750 providing service with highly abrasive and corrosive media. This configuration complies with NACE Standard MR-01-75 (1980) for corrosive service, optional 2-Wire shunt calibration.