I was looking for a cheap flashlight with a nice CREE LED that would ship quickly from Amazon and came across this Bluefire 1100 'Diving Flashlight' on Amazon.
It is fluro yello in colour, and comes with a lanyard, velcro strap, removable 3xAAA battery holder, and some spare o-rings.
I was able to insert a standard 18650 battery inside it (as an alternative to the 3xAAAs), and it worked perfectly.
The screw cap on the end is used to turn the tourch on/off and switch between the 3 modes of operation (strobe, low-power, full-power).
There is potentially better deals to be had on places like Aliexpress for a few bucks less - but this shipped/arrived next day for me.
I've got no idea how this functions underwater and don't plan to do so - I wouldn't rely on it though!
There is no focus mechanism on the beam, and the beam itself is pretty narrow - so good for targeting objects, but not good for flooding an area with light.
I've used one of these for a night dive before (borrowed from the dive shop). Worked fine for me.
A lot of the lower rating reviews are mainly because people may not know that some dive torches have a twist function to turn on (as oppose to a push button) and change the brightness and you're meant to do this before you enter the water, not when you're already submerged.