Winter can be brutal on your hands. This powerful hand warmer is your best bet for keeping your hands warm during cold winter days. The warmer features three heat settings, reaching up to 140℉, and can run for up to 12 hours on the lowest setting. The warmer can also serve as heat therapy for people with rheumatoid arthritis, Raynaud's disease, or menstruation. It also works as a power bank for electronic devices thanks to its large capacity battery.