The switch is a tail-cap "twistie." Twist on, med, then on/off quickly goes to low, then on/off goes to high. I don't know if it's "waterproof" since few lights truly are. It could probably be dropped in a stream and fished out fairly quickly without problems.

The med mode is great for most things. Hi is good out to maybe 30 yards (in a suburban environment) before it starts to get drowned out with ambient light. This is a floody light with a decent hotspot, not a true "thrower" like a spotlight.

The low is great for around house at night. I use it as a "night light" in the hospital call rooms on my overnight shifts. Bright enough to see everything, not bright enough to keep me awake.

rechargable AAA's do well in it. Nice, cuz I can just change them every few weeks and not worry about it dying.

Another nice thing is the tailcap comes off, if you want just a little more room for the Altoid tin.

ITP has 2 other versions of the same light, one with a tailcap mounted keychain-type attachment.