HALCYON REGULATOR H-50D FIRST STAGEThe H 50D is a high performance diaphragm design that is fully sealed and purpose built for harsh conditions, like ice or environmentally contaminated environments. Balanced, sealed diaphragm Dry balance chamber Two HP ports, four LP ports 300 bar DIN, compatible with 40% Nitrox Bench testing by an authorized Halcyon regulator service technician is recommended prior to use