where are they sold in the U.S.?
what brands are available?
is their output the same as 2 123a batteries? like in a SF FURY?
One 16650 replaces two 123a’s .
They are a (3.7 volt) lithium ion battery that work just fine in a* regulated torch* and yield same brightness as two 123a’s (6 volts)
I use one 16650 in an EagleTac P20C2 instead of two 123a’s.