If it comes with 2 x CR123A's, then you are probably looking for a 16650 cell. An 18650 cell will only fit if the inside diameter of the tube is 18 mm. CR123's are only 16 mm.
Yes , i know a 18650 is bigger then a cr123 , but i have also some 17650 batteries i use in my streamlight argo hp (it fits and works) , but i dont know if 3.7 volts will work in the protac hl (2 x 3 volts)?
Thanks Marc
I have the streamlight argo hl (normal with 2 x cr123) but a 17650 also fits and it works fine with it.
But i dont have (yet) the protac hl headlamp because i dont know a 18650-17650 will fit or work with it?
I use the headlamp, but I have always been under the impression that CR123 was the only acceptable cell, so I bought boxes of them on Ebay, and pretty cheap too.