its led's at the botton of the bottle they said it them self on there site but it would be cool to get a few bottles and re use it and replace the battery's and take it to a night time vape party it is something most ppl have not seen or would think of so you should be the life of the party with the bottle till ppl get bored of it
Mojo's juice may be delicious, dunno, but when I see gimmicky things like that, it makes me think that the product itself (in this case, the eliquid) is complete shit and the gimmick is the only way they can sell the stuff.
Useful for refilling your tanks in the dark, I suppose.
Oh and for those night time vape parties too, of course.
A rescue beacon when you're lost at sea as well.