NEXTORCH 3400mAh USB direct-charge 18650 battery changes the traditional way of battery charging, able to be recharged through a USB cable connecting the computer, wall charger, in-car charger, portable power bank and other equipments, also being compatible with 18650 battery charger; its triple circuit protection prevents overcharge, over-discharging and overheating to making the use more secure and reliable; the brand new large-capacity battery with compact structure design is available for the vast majority of flashlights using 18650 Li-ion.