This is a USB smart charger designed for 18650 lithium batteries. It features light indication and has a USB plug. The output voltage is 3.7-4.2V, making it compatible with various battery sizes including 10440, 14500, 16340, 16650, 14650, 21700, 18350, 18500, 18650, and 26650. Please note that the product does not include batteries.