I got one of those flashlights from Liion. Tried it with an 18650 and the bulb end got too hot to touch. It was bright though.
To everyone using the unprotected cells in their led flashlights, I would caution against it. So many things can happen, from explosion to just burning out your led. There is no regulation in the unprotected cells, so they can over draw, over discharge, over heat, among other things in the led lights. I would take some time and educate yourselves on this. I know you are all experts on batteries for our mods, but the led lights are a different animal, that imho wouldn't use anything but a protected cell with.