Elon Musk is excited about the Tesla Semi Truck. Although the CEO is trying to save details for the big reveal later in the year, he couldn’t help but leak a few details on Wednesday as to why the all-electric truck is going to be an impressive vehicle. And it involves the Tesla Model 3.

“I don’t want to jump the gun on the Tesla Semi Truck unveiling later this year, but I think it’s going to be an incredible product and we’ll defy people’s expectations of what an electric truck can do,” Musk said during the company’s first-quarter 2017 earnings call.

Musk is confident the truck will appeal to fleet operators due to a lower cost per ton per mile. Most of the truck will be built out of Model 3 parts, the $35,000 electric car set to enter production this July. Tesla will produce the Model 3 at a high volume, reaching 10,000 cars per week in 2018.

“Most of that semi is actually made out of Model 3 parts, by the way,” Musk said. “It’s using a bunch of Model 3 motors. We’re revealing too much about the future of it but … we’re able to use a very high-volume vehicle and then combine several motors to have something that I think is actually going to have a very good gross margin.”

That’s just not something that can be done with a traditionally designed vehicle with an internal combustion engine that runs on fossil fuels; it’s a view into Musk’s vision for the future of electric, battery-powered transportation.

Musk capped off his comments by stating the obvious: “You can’t do that with a traditional truck. It’s actually allowed us to put out a very compelling product that has low unit cost.”

Tesla Pickup Truck

The company is also working on a pickup truck, set for release sometime in the next two years, but the semi truck will launch first to demonstrate the potential of electric transportation to the general public. The semi truck, Musk claimed, will save ten times as much on hydrocarbon emissions than the pickup truck.

“In fact I’m highly confident that all transport will go fully electric [with] the ironic exception of rockets,” Musk said.

Cost is not the only area where the truck may innovate. Earlier this week, it was revealed that Tesla has written to the California Department of Motor Vehicles to get permission to test heavy autonomous vehicles, making the truck a potential candidate for self-driving technology.

It’s not the first time Musk has let slip details about the truck. In a TED talk last week, Musk explained how the vehicle won’t handle like a traditional truck. It’s incredibly nimble, there are no gears involved, and it’s got enough torque to overpower any diesel semi.

“It’s quite bizarre test-driving,” Musk said during last week’s talk. “When I was driving the test prototype for this truck, it’s really weird because you’re driving around because you’re so nimble and you’re in this giant truck.”

Watch Musk talking about the Tesla Semi Truck here:

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