Ambient electricity

What is "ambient" here? Thanks for helping

Other Considerations Kailo uses ambient electricity of its natural environment, so i doesn’t require a battery, and it doesn’t have to be plugged in. And as you can probably imagine, Kailo patches are highly durable. When they’re treated with care, they should be able to last for years before eventually needing a replacement. That’s certainly more use-time than you get out of a couple of pills.