I got it from a place called component-shop.uk - thats were I got the battery from too. its just a small chip that has LED's on it, its supposed to be for mounting on radio controlled cars so you know when the car's running low. However it ment to be for the battery pack that is in the pic. I thought let me stick it on the battery so I know when its running low since guessing is not practical when your shooting video / photos.