For $15, I took a chance on one of these (26650 batteries cost me another $6). Typical garbage o-rings in the cap which I replaced (with three sealing o-rings). I'll do the front end when I need to open the head. I used it for a week in Bonaire as my daytime light because the reflector makes a very tight and bright center spot (maybe 5 degrees) with a big immediate step to a large dim peripheral. It was good for poking into dark hole in the daytime and went the full week without recharge. I guess I'll see how long the switch lasts before I have to figure out how to rebuild it.
At that price, I was going to buy more but decided it is not what I want for night use.