I recently bought a laser that that requires 2 16340 batteries. I was wondering if i could use the more supported 18350 in its place. It should be noted that it is a more powerful version of a laser that uses one 18650.
Yep they are the same voltage the 18350 is just 2mm wider and 1mm longer than the 16340
The first two numbers tell you the battery diameter and the last three tell you the length.
16340 is 16mm wide and 34.0mm long
18350 is 18mm wide and 35.0mm long
18650 is 18mm wide and 65.0mm long
So 68mm ( 2 x 16340 ) vs. 65mm ( 1 x 18650 ) in length means your battery springs take up.......rather compress an extra 3mm which is typically no problem as there is usually a battery spring at each end.