NiteRider's Lumina 800 OLED guides you safely home. This bright light puts out up to 800 lumens for up to 18 hours and weighs in at only 172 grams! It attaches easily onto handlebars (up to 31.8mm in diameter) or a helmet so you can be ready to head out the door in no time. There are five modes to choose from: high, medium, low, energy-saving walk, and flash. You can charge it off a computer's USB port, and should you throw it in a bag for later use, the Lumina's lock-out mode ensures it won't accidentally turn on and waste battery life. The OLED displays battery-power percentage remaining, battery-power time remaining with selected light level mode, and Light Mode Level.