13I n t r o d u c t i o nYour HELiOS® Marathon H850 Personal Oxygen Systemis designed to store and deliver oxygen at a prescribedrate. The system consists of the H850 Portable and aReservoir.It is recommended that you breathe your prescribedoxygen rate from the H850 Portable. The H850 Portablecan be supplied with oxygen for you to breathe intwo ways.1. You may fill the H850 Portable with liquidoxygen so you can be free to move about yourhome or leave your home for extended periods.2. You can connect the H850 Portable to the HELiOSReservoir. See the section Connecting the H850Portable to the HELiOS Reservoir.The H850 System was designed to maximize yourfreedom of movement. You can fill the H850 Portablewith liquid oxygen from the Reservoir every day to use asfar from the Reservoir as you desire.When you are in your home and not moving about, suchas in the evening or while you are sleeping, you areencouraged to connect the H850 Portable to a HELiOSReservoir with an oxygen supply line (demand modeonly). When the H850 Portable is connected to a HELiOSReservoir in this manner, the oxygen you breathe issupplied by the Reservoir.Your oxygen supplier or home care provider must refillyour Reservoir periodically depending upon your rate ofoxygen use.