I can't use rechargeable batteries in my 4sevens light. :-/
Sent from Ash forum mobile
Is it a Mini X, or another type of Mini 123?
Otherwise, all 4Sevens regular or tactical lights will have a driver that can handle .9v - 4.2v so you can use a 16340 with the low voltage heads, and the high voltage heads are 3v - 9v so you can use two 16340's with them.
If it is a Mini, I'd definitely stay away from RCR's then... I've ready plenty of stories of people frying their minis by running then on 16340's or 14500's.