There's 2 different kinds of CR2
batteries.. Ones that are native 3.0 volts. I think maybe Tenergy and sony make some but I'm sure there are others..
The other style is a regular 4.2 volt li-ion cell with it's output regulated down to 3 volts. This type is typical of ultrafire and trustfire batteries and will work great on the AG-126 but the native 3.0 volt will not..
hoog