The only thing I have to add to this thread is about cold temperatures and manual lockout. I used to leave several lights with 18650 30 Q’s in them as part of a winter survival kit. I would always do a manual lockout so as to not have any drain while not in use. This past winter on a very cold night (about –25 C) I needed to use one of the lights. When I twisted the tail cap to once again use the light, the grease on the threads as well as the O ring were both frozen and the O ring tore and needed to be replaced once I warmed up the light. Not a big deal but something to consider if you may encounter the same conditions as I did.