Tesla CEO Elon Musk says his company will unveil its electric tractor-trailer truck this September, calling the vehicle “seriously next level” and praising the Tesla team for doing “an amazing job.”

He also revealed that Tesla will show off an electric pickup truck in “18 to 24 months,” and that the next Tesla roadster sports car will be a convertible.

Tesla Semi truck unveil set for September. Team has done an amazing job. Seriously next level. — Elon Musk (@elonmusk) April 13, 2017

Musk said last year in its second quarter earnings report that the company would be unveiling the Tesla Semi as well as a Model X-based Tesla minibus at some point in 2017.

“We expect to unveil those for the middle of next year, maybe the next six to nine months type of thing. And then [we’d] have a better, more fleshed-out plan for when those would enter production,” Musk said on the call last August. The Tesla CEO had mentioned a possible unveiling in 2017 when he announced the vehicles in his updated “Tesla Master Plan” — a follow-up to the goal-specific mission statement that he published for the company back in 2006.