The EcoFlow DELTA 2 extra battery doubles the capacity when connected to a EcoFlow DELTA 2 portable power station. This can have the effect of you increasing the batteries capacity from 1024Wh (standard) to 2048Wh (DELTA 2 x 1 DELTA Extra Battery). Or add on the EcoFlow DELTA Max Extra Battery to hit 3040Wh. EcoFlow DELTA extra battery Capacity: 1024Wh. Features: Battery capacity 1024Wh Doubles the capacity of the EcoFlow DELTA 2 Can increase the batteries capacity from 1024Wh to 2048Wh Silent & zero emissions rechargeable LFP (LiFePO4) battery Fast charging via mains, 12v car adapter or solar panel (optional) Specifications: Dimensions: H:27.0 x W:40.0 x D:21.0 cm Colour: Black Guarantee:5 years Material: Plastic Casing / Aluminium Chassis Model Number: ECOD2EB