Brass wetted parts for measuring non-corrosive liquid and gas pressure Circular dial is filled with glycerin and enclosed in a stainless steel 304 case for corrosion resistance Measures pressure with single (psi) or dual scale (psi/kPa)/(psi/bar)/(Hg. vacuum/kPa)/(Hg. vacuum/bar) Display accuracy is + or - 2.5% of full scale value for the 1.5" (40 mm) and 2" (50 mm) gauges, and + or - 1.5% of full scale value for the 2.5" (63 mm) and 4" (100 mm) gauges Lower mount or center back male connection with 1/8", 1/4", or 1/2" NPT rate with restricted orifice