Set up to 90 minutes of reading time, after which, the light will turn off automatically. Great if you tend to fall asleep reading. Read without disturbing others or having to switch off your lamp when you're done. Not your typical dim book light, this sleek unit features two bright LEDs that last 100,000 hours. Clips onto your paperback or hardcover book. Runs on three AA batteries (sold separately).LED Light The bright white LED lights illuminate the page you are reading without disturbing those around you. Great for long flights, or for those who like to read while their spouse sleeps. LED lights last 100,000 hours. LEDs do not heat up like traditional incandescents, so there is no danger if you fall asleep and the light tips onto your book or blanket. Timer Feature Programmable in increments of five minutes, up to 90 minutes. The digital display shows the remaining time. The light will automatically shut off at the end of the time, so you never need to wake up to find you left the light on...again.