Good product. It have some good features like: 1) It has built in battery which is 3.7V, 3000mAH lithium-ion and can be replaced. 2) Sometimes we forget to remove the plug, and the device gets overcharged. So it has a feature that, if the device's charging gets full, the device gets discharge and this feature called as Deep discharge protection. 3) It's life of led is upto 5 years.