Its nice to see larger RCR123A's [ if you can still call them that ] , anyhow I got myself a pair of 18350,s just to see what the go was . Now the 18350 is some what larger than the usual run of CR123A's :
18350 = 1.4inch long and DIA 0.72inch [ 35.56 - 18.29mm ]
This battery will not fit any of my EDC lights , but will fit 18mm bodies just fine , such as my later L2m [ 18650 ] and my UF501A lights .
These batteries cost about the same as regular 16340's and if you have a light that can handle them , then they do offer better run time and regulation .