Rechargeable and fully charges in 3 hours with included micro USB cable. Battery Life: High 10 hours and Low 45 hours. Two energy efficient LEDs cast bright warm light. 100,000 hour lifetime LEDs and no replacement necessary. Constructed of flexible and durable silicone and ASB plastic. Flexible neck. Precisely engineered optical grade lens spreads light evenly. Three light levels with step dimming. Ideal for large and medium sized books, travel, marathon reading sessions (long battery life), and bright warm light.