You'll never have to worry about your Christmas tree running out of power again. This product is ideal for the LED which powered by 2 or 3 AA batteries | A good substitute for AA batteries, Saving money, not need to pay for battery replacement any more. | The wire from the battery is very thin so it worked perfectly to go under the plastic battery compartment cover. | The wire about 12ft, convenient for indoor & outdoor use. | Please view the third image before you use, the black "battery" is for current-limiting.