Very happy to have scored this at a local estate sale! The tank has been confirmed via email by the great British adventurer David Hempleman-Adams as one that he himself carried on his back to the summit of Mount Everest in 1993. The tank was apparently a gift to a close friend and supporter. This is a fantastic artifact and as a fellow mountaineer (albeit a very junior one) who has hiked the Everest region, I am very proud to own it. Please note, the time of summit is actually well documented to be 11:38 am, not 9:38 am, and he admits that he must have spaced that detail when it was written on the tank during the return flight.