Features: 1. Two working modes: divided into outdoor portable power supply and indoor UPS power supply. 2. As outdoor portable power supply, the motherboard is only powered by lithium battery. The maximum external power supply capacity is 5.1V 2.5A. 3. As indoor UPS power supply: insert Micro-USB into ordinary 5V 2A Power adapter, and the external output USB-A interface can output a maximum of 5.1V 3A. 4. 4+2LED for charging and discharging, and battery power display. 5. The motherboard integrates overcurrent and overdischarge protection. 6. The external output port has a self-recovery fuse to prevent the for Raspberry Pi from being burnt due to an external short circuit. 7. When the total current of 2 USB output ports reaches 3A, the self-recovery fuse will be fusing. When the external port is no load, the 5V output will automatically restore. Specification: Condition: 100% brand new Battery: 1 x 3.7V 4000mAh lithiium battery Package Weight: Approx. 122g/4.3oz Package list: 1 x Lithium Battery Expansion Board 1 x Lithium Battery 1 x Set of Installation Accessories Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. Two working modes: Lithium battery expansion board is divided into two working modes, outdoor portable power supply and indoor UPS power supply. PMU over-discharge protection: When the voltage of the lithium battery is lower than 2.8V, the PMU judges that the battery has been over-discharged and automatically cuts off the 5V output. Use: When the total current of the 2 USB output ports of the UPS board reaches 3A, the self-recovery fuse is blown. When the external port is empty, the 5V output will automatically recover Self-recovery fuse: Raspberry Pi battery expansion boardd The external output port has a self-recovery fuse to prevent the Raspberry Pi from being burned out by a short circuit. The motherboard integrates overcurrent and Maximum external power supply capacity: As an outdoor portable power supply, the motherboard is powered by lithium batteries only, and the maximum external power supply capacity is 5.1V 2.5A. As an indoor UPS power supply: Plug the Micro-USB into an ordinary 5V 2A power adapter, and the external output USB-A interface can output up to 5.1V 3A. protection.