The Anfibio Multil has a built-in, internal battery that provides operating time of 9-19 hours. A charging adapter and cable are provided in the package to charge the battery. It can take anywhere between 4-6 hours to come to a complete charge. You can also use a power bank with the metal detector, but when it’s connected, you won’t be able to use wired headphones or submerge the detector. You can also purchase a waterproof battery pack separately that connects to the back of the armrest. On the battery pack is an input socket to connect wired headphones. It takes 4x AA batteries.