If you’re wowed by the 520-mile all-electric range of the new Lucid Air Dream Edition, your mind will be blown by the new, slinky Mercedes-Benz Vision EQXX that manages to eke out 621 miles on a full charge. While it’s just a concept for now, the EQXX’s efficiency is very real. It gets a new electric drivetrain that delivers 95% efficiency, meaning the vast amount of battery energy goes to the wheels. It also has a smaller but denser battery that takes up less space and has less volume, as well as a nearly unimaginable 0.17 coefficient of drag that makes it truly slippery. Some of the key materials used are recycled and plant-based in order to reduce its carbon footprint. Most importantly, at least to us, is the way it looks. It could be mistaken as a a long Porsche Taycan or a McLaren Speedtail, frankly. The EQXX will make a 621-mile test run in the coming months, and the car could very well become a reality.