Though a few daring owners have made the attempt to tow a trailer with their Tesla Model S, the electric automaker recommends against it…to the point where it could void your warranty. But the Tesla Model X is supposed to be the first production EV with towing capabilities…and judging from the above picture, the Model S might benefit too.

This undescribed image popped up in the r/teslamotors subreddit without much in the way of a description, though I’d wager these images are from around Fremont, California, where Tesla is located and where I-680 runs through (at least in part). Less likely, but still possible, is that this Model S is actually testing either software or hardware for the upcoming Model X. Considering the cars will share much of the same platform, drivetrains, and (presumably) software, it could honestly go either way. But I see a Model S, so let’s go with that for now. And yes, that’s a test mule; look closely at the wheels and you’ll see sensors measuring…something. Definitely a test car.

There’s been some question as to just how much weight the Tesla Model X might be able to carry. While it’s impossible to know just how much weight this test mule is towing, the empty weight of the 12 x 6 trailer the Model S is towing is 1,730 lbs, and its obviously not empty. That particular U-Haul trailer is rated for up to 2,670 lbs of payload, giving it a gross vehicle weight of 4,400 pounds. While obviously not loaded to the brim, there could be almost anything in those plastic crates, from lead bars to pillows. It is also the largest trailer U-Haul rents out.

That said, I feel confident in asserting that the Tesla Model X (and maybe also the Model S) will be able to tow between 1,700 and 4,400 pounds. That’s a pretty solid towing capability to be sure, and it could potentially be even more. On the other hand, towing could be one of the issues causing delays in the delivery of the Model X.

But even without Tesla giving us any hints about the towing capability of the Model X, a single picture can say a whole lot.