For gauges with MIP, GY40 fill is standard for liquid filled gauges. Cleaning for Oxygen Service O2 is available only for dry or HL Halocarbon filled gauges.5" Brass Case, Copper Alloy Internals, 200 psi/bar, 1/4 NPT Male Back Conn, Glycerin Filled, 0. Pressure Gauge, 4 in.