Mercedes-Benz has teased an all-electric prototype dubbed the Vision EQXX that promises to be the most efficient electric car ever as well as the one with the longest range.

The car manufacturer shared teaser images and preliminary details about the prototype during its 2020 strategy update presentation. During the presentation, it suggested it could travel from Beijing to Shanghai, a journey of roughly 750 miles (1,207 km), on a single charge.

The Mercedes-Benz Vision EQXX is being developed by a team based in Stuttgart that is receiving support from the AMG High Performance Powertrain group in the UK that has motorsport experience with electric motors.

Read More: Mercedes Confirms Electric EQE Sedan, EQE SUV, And EQS SUV Among Other EVs

Engineers behind the project have revealed the key to the Vision EQXX’s range will be efficiency rather than a massive battery pack.

“The easiest way is to put a bigger battery in the car, but it leads to diminishing returns. The key is efficiency of vehicle and powertrain,” they said.

“We have set up a group of our engineers to take on an extraordinary task: to build the longest-range and highest-efficiency electric car the world has ever seen,” added Mercedes’ research and development boss Markus Schafer. “This is a serious project, chasing next-generation technologies. We intend to incorporate the learning into the next generation of series production cars.”

The Mercedes Vision EQXX is tipped to be a one-off prototype rather than a production model. With that being said, the automaker has confirmed that things it learns from the prototype will filter across its range of electric production cars.