Yip, have seen htem once before, from a flight ALS doinig duty in Zambia. He pretty much explained to me what you posted, as well as that it provides 20 degrees to the angles achieved with a standard lscope in order to align the axis. May be it allows for less manupulation of the c-spine with the end result being the same??I have never used one, but i think it can find a place in my kit somewhere.