SugarRayThe numbers in battery naming are dimensions. The first two are diameter, the last three are length. The inside diameter of the light is less than 18mm, so 18650s will not work. If, however, you found a 16650, that would replace the CR123s nicely. It's less common than the 18650s, but they do exist.
It is not programmable, but it does have three modes, and memory.
XenoMuseSo will this take both 3.6/3.7v RCR123 batteries? What about this high output RCR123 aka (IMR16340) that I use in my s1r Baton 2 that makes it where a small edc light can get up to the 1000 lumen output using just 1 of these.