Good, sturdy build small flashlight. I speifically choose single mode "on-off" version, in my opinion it`s better than having to switch all the modes around (especially useless strobe). The flashlight battery tubes inner diameter is slightly bigger than the regular AA battery - 17mm vs. 10mm of AA, thus AA batteries will dangle a bit inside. I think it can even fit 16500 Li-ion batteries (at least I`ve tested it with 14500 Li-ion and it works, so no problem with 3.7V).
all ok