Elon Musk has revealed the oft-delayed Tesla Semi has finally gone into production.

The announcement has been years in the making as Tesla originally unveiled the Semi in November of 2017.  It was slated to be launched in 2019, so it’s almost four years behind schedule.

Musk said deliveries will begin on December 1st and the first Semis will be going to PepsiCo. The food and beverage giant confirmed the news to Reuters, saying the vehicles will be used at two different facilities in California.

Also Read: Tesla Releases Updated Semi Photo Gallery, Shows A Handful Of Design Changes

It remains unclear how fast production will ramp up, but Musk promised the model will have 500 miles (805 km) of range and be “super fun to drive.” We’ll likely learn more details closer to launch, but the Semi features a tri-motor powertrain that delivers “instant torque and unmatched power at any speed, so drivers can merge safely and keep pace with traffic.” The company has also said the model will be able to accelerate from 0-60 mph (0-96 km/h) in 20 seconds, when fully loaded, and maintain highway-level speeds even when climbing grades of up to 5%.

More importantly for fleets, Tesla says charging with electricity is approximately 2.5 times cheaper – per mile – than refueling with diesel. This could potentially save them up to $200,000 ($180,241 / €204,837) within the first three years. The Semi also promises to minimize downtime as it can receive a 70% charge in as little as 30 minutes.

As we reported in August, the Semi’s design has changed a bit over the years. In particular, the model now comes equipped with massive side mirrors and an updated greenhouse. The interior has also been revamped as it has a new console and a lightly revised steering wheel.