Summary
18650 lithium rechargeable battery, 2200 mAh.
The picture shows all the batteries our UV lights take, so that you can see the relative sizes. From left to right: 26650, 18650, AA, AAA.
The 18650 is pictured second-from-left, i.e. it is "Battery, rechargeable lithium 18650" - you will not get all four batteries!
IDEA: buy two batteries and one charger, so that you always have a spare battery handy.
Detail
When you buy a UV light from us, it comes with batteries.
Some take AA or AAA batteries only (we use a good quality alkaline battery, as pictured). These are included in the price of the UV torch.
Some take a 26650 battery only. A battery and a charger is included in the price of the UV torch.
Some can take standard AAA batteries (included in the price) or a lithium 18650 rechargeable battery (optional). If you would like the optional 18650 battery - this is it.
Don't forget to buy a charger if you don't already have one.
How long a battery lasts on one full charge, is listed (in great detail!) on each product description.
Links
Useful links:
Battery charger
(article)
of what you will see with UV lights