The Faraday Flashlight uses no batteries or bulbs. Instead it uses energy and induction to produce a bright light using efficient LED technology. Just shake the light for about 30 seconds and the Faraday Flashlight will provide about 5 minutes of light. During prolonged use it can be shaken for 10-15 seconds every 2 or 3 minutes giving you an unlimited supply of light. The Faraday Flashlight requires no maintenance. You can leave it in your car, home, boat or RV for a long time and it will still be ready to produce light when you need it. The bright LED will last for thousands of hours and provide a lifetime of service. Each and every light is hand tested to insure dependability and long life. Actually it should never need replacement.