16340 is it the same as CR123

As above, I have just ordered a xtar wk21, which according to youtubby takes a 16340 cell, which the uploader/author describes as a higher voltage longer lasting CR123, I’m confused I thought they were the same cell ?
I have a lot of AW 123 Li Ion of 3.7V.
Your advice would be most appreciated, so if I need to I can get these 16340 on order, thanks all

Same size different voltage.

Also, I’ve found that the 16340 cells have about 40-50% of the capacity of a disposable CR123 cell. E.G., 550-700 mAH vs. 1400 mAH or so…

Since posting I have been looking on various sources, some list a CR123 and a 16340 as the SAME battery, most list the CR123 as 3.0V, and the 16340 as 3.7V, but there is variation even to this, my AW is marked as ICR123, 3.7V, though a lot are listed as 3.0V, all the 16340 are listed as 3.6 or 3.7V.
It gets even more confusing looking at dimensions, as the 123 is 0.64” X 1.3”, versus the 16340 at 0.71” x 1.3”, odd thing is the 123 weighs 1.4 oz compared with 16340 at 2.65 oz.
My suspicion is the 123 should be 3.0V, as one of mine is, a brand called DIGITAL, and the 16340 is the 3.7V version of this, owing to most things being able to take either 3.0 or 3.7 this has caused the confusion, well that’s my theory anyway.
I suppose if things are designed for 3.7V they will still work on 3.0V in most cases.

My AW 123, 3.7V are marked as 750mah, my DIGITAL brand is marked as 3.0V and 650mah, the AW is defo heavier though ?

A fully charged 16340 should be around 4.2 volts.

If you want disposable batteries go with CR123A’s and if you want rechargeable buy 1 or 2 good 16340.

I haven’t actually looked up the light you are getting but check the voltage range, if it cuts off at 3 volts the CR123A wont be much use.

Generally CR 123 are 3 volt disposable non rechargeable, RCR 123 or 16340 are 3.7 volt rechargeable Li ion there is also a different chemistry that is 3.2 volt and requires a different charger.
16340 = 16 mm dia. 34 mm length final 0 means cylindrical cell.
hope this helps

Edit 3.7 nominal 4.2 hot off the charger

there is also the lifepo4 chemistry @3.2v nominal 3.5v fully charged. ive seen them marked both rcr123a and 16340. its a “safe” chemistry, not sure how capacity compares to cr123a or the liIons the same size though

My AW’s are marked 3.7V, but are in fact 4.2 when charged with my Ultrafire or Trustfire charger, both the ICR123 and the 18650.
I never use primaries as no point for me.
This lights works from 2.75V to 4.2V says the makers website.

CR123 is a primary battery, RCR123 stands for rechargeable CR123 and is used about any battery in CR123 that can be recharged. 16340 is a size specification and is usual used about rechargeable batteries in CR123 size, i.e. exactly the same as RCR123.

But the RCR123/16340 specification is used about a lot of different batteries:

1) LiCoO2/ICR and LiMn/IMR batteries that are 3.6/3.7 volt nominal, but 4.2 volt of the charger.

2) LiFePO4/IFR batteries that are 3.2 volt nominal (often marked 3 volt), but 3.6 volt of the charger.

3) Batteries from 1) with a voltage drop, i.e. voltage is between 0.4 and 0.7 volt lower than 1).

The size does also vary with a few mm, i.e. not all RCR123/16340 can fit instead of a CR123 cell and not all equipment will work with the higher voltage.

The Xtar WK21 uses the ones from 1) that is the same as the AW 123 batteries.

Thanks for you input HKJ and others who responded, it is very much appreciated, my baby is on it’s way now, WK21 that is.