I really like your idea, Christian, climbing in the mountains, it is already difficult but in addition to the lack of oxygen, it can be downright dangerous, and then it is not light to carry! And then I can imagine that if someone is running out of their own oxygen reserves, it offers more security. I think this would be really useful for beginners of the mountains too! In short, a big congratulations for this ingenious idea. Do you do the mountain too? What other problems can you identify? I would like to see what other inventions you can have ....