It's (probably) not really "powered" by water. The water is only working as part of a chemical reaction like any ordinary battery. Youtube user BigClive did a teardown of a "water-powered" flashlight in case you're curious as to what is inside:
https://www.youtube.com/watch?v=2OlzB4xN0GY
Re: FOURSEVENS Knight and Paladin - PK collaboration!
YES it steps down!
I got a Paladin recently, so I tested it with the included CR123 primary and a LiFePO4 RCR. I turned the light on high and timed the stepdown with a stopwatch. I don't have any sophisticated testing equipment, so these...
The O-rings are spares, in case an existing one gets worn out you can just replace it. The clip spins around if you don't tighten the tailcap all the way; if you tighten the tailcap the clip shouldn't spin around.
A while ago I bought the Nitecore D10 headband, although I'm not sure if they're still making them. Fits the D10 as well as most 1xAA lights easliy. I use it occasionally when I need to have both hands free.
I don't really think anyone would want to buy 30 batteries at a time! I'd imagine the thought process of the typical consumer when he spots this light would go something like this:
"Oh, this pole light is really bright! But it needs 30 batteries."
Put a pack of AAA's in the shopping cart.
And...