... Brass internal Glycerin filled Back connection Good quality Liquid filled Pressure Gauge:Case sizes: 1.5", 2", 2.5", 3", 4" and ... size; bottom, back, left and right side connection Available ranges: vacuum and compound through 500psi, 600psi, 5000psi, 10,000psi and so ... 2.5% accuracy, U-Clamp, restrictors. back connection glycerin filled Pressure Gauge