No battery required; Just like riding a bike! Your hand is the battery of this device. The motion of your hand rotating the Spinner is similar to making ice cubes swirl inside a glass. The essence of operating the Spinner is not about how fast you rotate your wrist. It’s about how to synchronize your wrist rotation to the momentum and timing the rhythm of the rotor’s gyration. The faster the rotor spins, the easier it is to operate. Make sure you start the Spinner with sufficient speed.