BUILT-IN RECHARGEABLE 450 mAh LITHIUM-ION BATTERY. With 40 lumens, adjustable arm, and lasting up to 12 hours on a single charge, Luci Core is a must-have solar task light BRIGHT AND LONG LASTING. Emitting 40 lumens of power via 3 cool white LEDs, and shining through a matte finish, this light provides up to 12 hours of light on a single charge, so you can rely on Luci Core whenever you need it. COMPLETELY SOLAR & NEVER NEEDS BATTERIES. Luci's built-in high efficiency solar panel means that no batteries are needed - ever. Recharge fully via solar or quick charge via USB (13 hours / 1 hour). Luci Core does it all POWERFUL, PORTABLE, AND TASK READY. With its 14 inch long adjustable arm, you can direct light however you choose. Task light, emergency light, overhead light, Luci Core does it all.