The Verilux Book & Travel Deluxe Natural Spectrum Reading 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 - Uses either 2 regular or rechargeable AA batteries (not included) - Operates battery-free via USB connection to computer - Book Light head turns 180º to shine light exactly where you need it - Available colors: Silver or White - Height range is 9" - 3.5" Compact size: 3.0" x 3.4" - 1-year limited warranty - Ingenious Design: Clips or stands and folds down to form its own protective, travel-ready case Book & Travel Computer and Reading 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 & 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.