This LHY Audio BATT-USB regulated linear power supply module uses four 21700 batteries with a capacity of 2000mAh (a total of 8Ah) and an ultra-low-noise LDO LT3042 linear voltage regulation chip with D45H11 PNP transistor. This linear power supply has two outputs: one on a USB-A connector and one on a DC 5.5/2.1mm jack connector. Their output power is shared and can reach up to 2x 5V 2A (total amperage of 4A if only one output is used). This means you can power your Hi-Fi equipment with an ultra-low-noise signal. The module itself is powered by 9V DC, also via a DC 5.5/2.1mm jack connector. A charge protection module completes this input.