This is Your thread, so now worries on topic. if it gets too wild we'll split. The system is meant to serve us, and not the other way around! Cool stuff by the way! It might be interesting to compare this setup with the US escape gear (Momsen Lung) and any others. I look at "parallel invention". My own personal survey of electrical plugs and sockets of modern times: USA = small and wimpy, with bad wire nut connections in junction boxes; UK = huge and chunky plugs, don't know about wiring; Australia = compact yet substantial, with really simple and secure screw connection inside boxes and switches. USA has good junction boxes, yet half the power of Aus, Aus has crappy exposed (internally) switch boxes. All do the same thing, and for practical purposes, equally well, but all are different!