I hate seeing people feeling ignored. It's all about size and voltage. I believe the 123 designation means they are the same size. But I think I've seen CR123a's in both 3 and 3.7V. Don't know what the LIR123a is but I suspect that the LIR may be a designation of the chemistry of which they're made. I've never actually used that size battery so take it for what it's worth.