For top quality manufacturing-
the AW
batteries come well recommended, of course..
I like a couple of the AW Lifepo4 3.2V blue batts for 6V, work great in my ggts with a standard joye 510 in the UFS.
Or occasionally 2 AW 16340 3.7V high drains, youch! (not w/ a SR atty though!)
their 18650's are all i use for 3.7V..but i've been doing 6V more lately as well..
I've been using these batts for a year now with no issues at all, and they have that pow. I am far from a battery expert, to say the least, but they do seem to provide steady power over the whole usage cycle instead of dropping off as much as li-ions seemed to, imo..
