The EcoFlow DELTA Pro Smart Extra Battery is a 3600Wh additional battery designed specifically for the DELTA Pro portable power station. It allows users to expand their power capacity up to 10.6kWh by adding two extra batteries. The battery can be conveniently recharged using various sources such as AC, solar, Smart Generator, car charging, and EV charging. It features a long-lasting LFP battery and is exclusively compatible with the EcoFlow DELTA Pro.