If you want to check out Steve Jobs and Steve Wozniak’s first ever product, book your travel to Michigan now!

That’s because The Henry Ford museum in Dearborn has acquired a rare 1972 Blue Box in an auction in New York City, and will be displaying it soon. The illicit device, which pre-dates the Apple-1 by four years, allowed users to make free long-distance phone calls by reproducing specific dial tones.

What was the first gadget Steve Jobs and Steve Wozniak ever manufactured and sold? No, we’re not talking about the Apple-1, but rather the “blue box,” a device which allowed users to make free long-distance phone calls by reproducing specific dial tones.

One such device is up for auction this month, where it is expected to sell for upwards of $67,400. That’s roughly 67 brand new iPhone X handsets if you want to do the math!