This is a super mini power bank mainboard compatible with 3.7V-4.2V li-ion battery. On-board micro USB port for battery charging and USB type A female output port supporting DC 5V 1A input and 5V 1A output. Just conenct it with a 18650 battery then you can get a portable power bank.
Input Voltage and Current: 5V 1A
Output Voltage and Current: 5V 1A
Compatible Battery: 3.7V-4.2V lithium battery
Board Size: 22 X 17 X 11mm/0.87 X 0.67 X 0.43inch(L*W*H)
1X Mini Power Bank PCB Board