Just a word of caution: I have 3 Klaurus 16340 cells with built in USB charging. There is a distinct warning NOT to charge them other than via the USB port. I had not remembered this and put 2 into my VC4 charger-both cells swelled, splitting the wrapper & were very hot to touch when I removed them. I know your Question was about an Olight 16340 but wanted to share my experience that even if one cell is OK in a conventional charger, not all cells are...