Yesterday, we got a slightly better idea of the range of battery options for the Tesla Model 3 after CEO Elon Musk confirmed that the vehicle’s wheelbase can’t support a 100 kWh battery pack like the Model S and X.

But specifics are still unclear since it leaves us only with a vague range of < 60 kWh to < 100 kWh for battery options. Today, we get some actual numbers for the first time as we learn of a Model 3 test mule.

Sources familiar with the program confirmed to Electrek that Tesla has been testing third generation systems in a Model 3 test mule configured with dual motors and a 70 kWh battery pack, which would make it a “Model 3 70D”.

The only working prototypes that Tesla allowed people to ride in have been the gray prototype and the matte black prototype both unveiled at the original launch event in March 2016.

At least for the gray prototype (pictured above and below), an engineer giving test rides confirmed that the drivetrain was an all-wheel-drive with dual motors, but they never confirmed the size of the battery pack.

It’s not clear if the Model 3 70D test mule is one of those prototypes since, of course, they had no badging, or if it’s an all new vehicle.

The fact that Tesla is testing a Model 3 with a 70 kWh battery configuration doesn’t necessarily mean that it would be an option after the test mule program is over, but it’s the best indicator of an actual Model 3 configuration we have so far.

We asked Tesla to comment on this report and on whether the test mule configuration was an indicator of the Model 3’s battery options, but a spokesperson told us that “Tesla hasn’t released further details on battery options for Model 3.”

A Model 3 70D configuration could enable close to 300 miles of range on a single charge, which would be in-line with our report from last year that Tesla was aiming for the high-end version of the car to have over 300 miles of range.

Tesla’s dual motor configuration is also more efficient than its rear-wheel-drive option since it can adjust the torque between the two axles. Considering the vehicle is about 20% smaller than the Model S and Tesla aims for a 0.21 drag coefficient, it could achieve something close to ~230 Wh per mile on average, which would add up to about 304 miles on a charge. That’s only our estimate.

A Model 3 70D would certainly be more expensive than the $35,000 base version. We know that Tesla aims for the 2wd base vehicle to travel over 215 miles of range on a single charge. Based on the similar efficiency estimates, it would make the pack between 50 and 55 kWh. The Chevy Bolt, with much worse drag/aerodynamics, gets 238 miles from a 60kWh battery.

We should know more relatively soon since a final reveal event is expected in the coming weeks based on a comment by Elon Musk last year. At the event, Tesla is expected to release all the details about the Model 3 and possibly even start letting reservation holders configure their vehicles ahead of the start of production during the second half of the year.