FIL got a job as a security guard... graveyard shift driving/walking the grounds of a moth-balled prison a couple of nights a week. They are kind of strapped so I was going to hook him up with a good light. It is in a rural area and I expect the most challenging part of the job will be staying awake, not the type of the deal where he'll be running his light 6 hours a night. I was thinking a TK11 with a couple of R18650 cells and a charger. But I've generally had bad luck with rechargable anything, so I was wondering if I'd just be better off spending that money on two or three dozen CR123A cells... doubt he'll even burn through a set per week and I don't really see this being something he is still doing in 6 months.