The "O2PAK" is a small, non-pressurized emergency chemical oxygen generator from Combat Critical Care Corp. Designed for military, ESAR/CSAR and humanitarian operations, the O2PAK weighs approximately three pounds and will easily fit down in a pack. It requires no maintenance, mixing or filling and has a shelf life of 4 years. The one-time use O2PAK produces solid-state chemical oxygen to eliminate the risk of explosion and requires no electricity - there's no battery connection or anything to recharge. It's guaranteed to produces oxygen for 22 minutes minimum. According to the manufacturer it will operate at up to 40,000' altitude.
It has undergone a number of tests, including medical, ballistic, blast and fire tests. According to the manufacture, the O2Pak has undergone "...a significant amount of testings, among which we have the soak test, the burn test and the ballistic tests."
They further advise, "We are just waiting for the blast test, and we should be done."