Stainless steel case Brass internal Glycerin filled Back connection Good quality Liquid filled Pressure Gauge:Case sizes: 1.5", 2", 2.5", 3", 4 ... : phosphor bronze and brass Movement: brass Liquid: glycerine or silicon oil Connection: 1/8", 1/4", 3/8", 1/2", BSP ... size; bottom, back, left and right side connection Available ranges: vacuum and compound through 500psi, 600psi, 5000psi, 10,000psi and so ...