The Ametek/US Gauge 256025 is a 656 series liquid fillable gauge with a 30" Hg to 15 psi pressure max, 2.5" dial size, 1/4" NPT center back mount connection, stainless steel wetted material, and stainless steel case material. The 656 Series are suitable for corrosive environments in chemical, petrochemical, refining, power, marine, and food and pharmaceutical processing applications. Liquid filled pressure gauges provide users with a number of advantages in certain measurement applications. They are ideally suited for uses on equipment where excessive vibration and pulsation are encountered, such as pumps, compressors, machine tools, etc. The liquid fill minimizes the effect of these severe environments, protects the gauge internals, and provides continuous lubrication on the mechanism, all adding up to extended service life. Liquid filling also provides greater protection of the gauge internals from corrosive atmospheres.