Lead metaniobate exhibits properties not usually present in other types of piezoelectric ceramics such as its low mechanical factor QM and high coupling anisotropy (i.e., small values for lateral and planar coupling compared to longitudinal coupling). The material also has negligible aging, a wide range of operating temperatures and a low dielectric constant Lead niobate has negligible aging, which helps simplify circuit design. Wide variations in temperature have limited effect on its dielectric and piezoelectric properties making it ideal for high temperature applications. The low QM and and low dielectric constant of these materials makes them useful for high frequency work such as wide bandwidth sensors for high frequency pulse echo measurements that require a short pulse and critical resolution. Lead metaniobate compositions are widely applied in probes for non-destructive testing (NDT) transducers where low QM and clean impulse response are required. Underwater sonar equipment utilizes lead niobate because the material has a high longitudinal coupling compared to its lateral and planar coupling allowing it to generate a better response under hydrostatic pressures.