Function and compatibility 16V Direct Current input and output through a dedicated DC connector for charging and powering compatible devices. USB output on the same unit provides 5V at up to 2A to charge mobile phones and other USBpowered devices. Battery assembly and performance No welding required for the battery setup, which helps reduce internal resistance, improves discharge performance, and can effectively extend battery lifespan. Easy to use with 4 x 18650 or 26650 batteries designed to be paired in this box. Key attributes Function: portable battery box with DC input/output and USB charging capability. Compatibility: supports 4 pieces of 18650 or 26650 cells; no welding required for assembly. Performance: reduced internal resistance, better discharge characteristics, longer potential lifespan. Maintenance: straightforward cell replacement by using common cylindrical Liion cells. Use scenarios Outdoor and travel: use to power compatible devices at the campsite or on the move, and to charge phones via USB when access to mains is limited. Emergency backup: provide power for essential devices during shortterm outages or remote locations where 16V DC power is available. Field work or remote sites: reliable DC power option for equipment and USB charging needs when standard power is not readily available.