The Natural Spectrum Book and Travel Light is a 2.2 oz book light that slips into your purse, pocket or briefcase for flicker-free, glare-free indoor daylight anywhere. Clips to books or laptops for hands-free operation. The advanced cold-cathode bulb (included) never needs replacing. Fully adjustable with a unique double-articulating head, the book light head also swivels to place full spectrum illumination precisely on any surface. The Book and Travel Light also includes a built-in charger if you decide to use rechargeable batteries. When you plug it into your computer, the batteries will be recharged at the same time for an additional 4-6 hours of run time. Small print appears clearer and the high/low intensity switch allows you to tune the light for the specific application. It clips to books and menus or stands on its own. Natural Spectrum Book and Travel Light Features: Full spectrum daylight book light and computer light. Palm-sized travel light features exclusive Verilux technology that scientifically tunes light to the human eye to help improve vision, and reduce eyestrain. Book Light head turns 180 to shine light exactly where you need it. Clips or stands and folds down to form its own protective, travel-ready case. Operates battery-free via USB connection to computer. Uses either 2 regular or rechargeable AA batteries (not included). Natural Spectrum Book and Travel Light Specifications: Colors: silver or white. Height Range: 9 inches - 3.5 inches. Size: 3 inches x 3.4 inches. Warranty: 1 year limited.