Wow - just saw this - glad you didn't get hurt, @Teleclashter. I would think this might be a bit dangerous for a younger person, no? Do they have age/height requirements? And I had heard the different colors of the tubes were for "more" or "less" intense - and I THOUGHT I saw the blue was supposed to be MORE, but the experience @Ryno had in the blue tube seemed much "gentler"?