The Energizer Vision runs on 3 AAA batteries, which are included with every unit purchased. When in Low mode, the headlamp is capable of running for up to 50 hours! Imagine you are stranded on the side of a busy road and need to change a tire? You want to have a hands-free light that is reliable and long-lasting. This Energizer Vision won't take up much space in your glove-box, but you can feel secure in knowing that its long-lasting runtime is just want you'll need in an emergency situation. Additionally, AAA batteries are extremely easy to find and replace.