Personal Emergency Oxygen System with 4 CF Cylinder and two masks Keep this small 4 cubic foot personal oxygen system within reach, for safety in the event of unexpected failure or depletion of your main oxygen supply, or unexpected cabin depressurization. This system is designed to give you oxygen based on a cabin pressure of 25,ooo feet and will flow at this set rate for 20 minutes, so that you can have time to get down to a safe altitude where you can breathe normally under the conditions. Simple to use, when needed pull the ring and don the masks. The motion of pulling the ring pulls a cable that initiates the flow of oxygen to each mask. This system is able to be refilled after each use. This system comes standard with an aluminum DOT 3AL cylinder that has no life limits and requires a recertification each 5 years. The interface to the system is a standard economy rebreather mask, but can be upgraded to a TSO C103 mask or a TSO 64 type mask(please call for this upgrade). The PRO2 emergency systems are availabe in 2, 4 or 6 cubic foot configurations and the 4 or 6 cubic foot systems are available in single or dual user configurations.