Durable clip on light. Three warm white, energy-efficient LEDs. Accurate color rendering. Continuously dimmable up to 55 lumens. Durable LEDs last 100,00 hours. Precisely engineered optical grade lens spreads light evenly across pages. Flexible Silicone neck. Powered by 3 AAA bateries (included) or use micro USB cord (not included). Battery life approximately 16 hours.