[Rainer]

I have no interest in "changing your mind". That said, I'll tell you why I have no problem rocking a pair of twist on backup lights. First, mine require just a minor turn to twist on, at which point the threads are fully engaged. To flood it, I'd need to make something like five complete turns in the opposite direction. If one cannot figure out the difference, he shouldn't be tech diving. Second, they won't accidentally twist on underwater with increasing pressure like the H Scout lights. If for some crazy reason they did turn on, my team would notice within seconds. As far as turning on in a dive bag, I keep my lights attached to my harness. They don't move until I need them and it reduces the chance of the light accidentally coming on in transport. We check our backup lights before diving. We have spare batteries. It's just a non-issue. Four, a double o-ring sealed twist on has only one means of flooding, through the front of the light past those two o-rings. Unless you're a complete twit, you won't twist off the head of the light and thus you cannot flood such lights. They're rock solid. Taking a perfectly closed system then drilling a hole into it to add a dynamically moving switch is unideal. It's proven out by the numerous reported failures of such designs. Both the hole created by adding the switch, and the more complicated switching mechanism (compared to the simple twist mechanism) are failure points that many tech divers (DIR or not) would rather do without. As the depth of the dive increases, and pressures build, these potential failures become more and more serious.

For all these reasons, I have no interest in mechanical switch based back up lights.