I’m not a big fan of the Nano for a few reasons. Off not twisted far enough off, any pressure will make it light up and run down the battery. If you turn it too far off, I have had it come apart and lost half or the batteries.
A similar light that I find a little better is the Pelican 1810. But if willing to go a little bigger, there are several different variety of 10180 flashlights that I think are much better. The 10180 lights I have had (Jetbeam Mini, MecArmy) were brighter, less likely to turn on or separate and rechargeable.