DEBEL has designed and developed Helicopter oxygen system Mk-II to meet the requirement of aircrew engaged in flying Advanced Light helicopter (ALH), Light Combat Helicopter (LCH) and Mi-IV helicopter. The System consists of High Pressure Oxygen Source (HPOS) with various light weight composite cylinder to meet the space constraint of helicopter and its flight endurance. The system also consists of Chest Mounted Dilution Demand Breathing regulator (DDOR) Mk-I for Mi-IV and Panel Mounted Dilution Demand Oxygen Regulator (MK-II) for ALH and LCH.