We use LG brand 3500mAh capacity 3.7V 18650 batteries. Most other dive lights are using generic batteries have a capacity of 2200 - 2600mAh. That means our batteries have at least 30% more capacity.
We use them because we only want to use the best batteries available.
Capacity - 3500mAh (note that this is a nominated capacity, the actual capacity will vary, however the minimum is 3400mAh)
Nominal Voltage: 3.6V
Peak Voltage: 4.2V
Protected - Yes
The batteries come wrapped in an Aqua Lumo shrink wrap, but inside it is an LG battery.
The photo is currently still the Panasonic 3400mAh battery which we were using previously ... but bear with us ... we'll update that shortly.