The OKY3604-2 Module is a device manufactured by OKYSTAR which combines a charging, power bank, and USB in one unit. The module has a small size of 18650 and can produce up to 3V or 5V of power. This module can be used to power a variety of small devices, such as cell phones and other USB powered devices. It is also suitable for charging many types of batteries. The module also has built-in safety features, which includes overload protection, short circuit protection, and overvoltage protection.