A rare Porsche 959 prototype is up for sale in Germany.

The German company Mechatronic may specialize in restoring and selling classic Mercedes-Benz cars, but the store is currently selling a very special Porsche 959. Not your average 959, but a prototype of Porsche's first supercar.

First spotted by Motor1, this car is the seventh of 12 F-Series prototypes. Finished in ruby red, the car was used for hot-weather and electrical system testing in the United States and Europe. The level of testing was unusual for an exotic car at the time, but Porsche wanted to make sure the 959 could be used anywhere.

During testing, the vehicle on display was fitted with several interior layouts, including different seats. Extra wiring remained under the passenger seat, as well as mounting points for test equipment.

The prototype is missing several items from the production version of the 959. It is missing the power steering, fuel filler cap, ride height control, rear seat back, passenger side exterior mirror, alarm, and windshield washer.

Although Porsche destroyed most of the F-Series prototypes (Mechatronic estimates only three or four are extant), this car was imported to the United States and displayed at the headquarters of prominent Porsche dealer Vassek Polak. It was then sent to Japan for demonstration purposes, then to Belgium and then to England. It currently has 16,478 miles on the odometer.

The mechatronic did not list a price, but the car was offered at auction in 2018 with an estimated price of $1.3 million to $1.6 million. At auction that same year, even the wrecked 959 production car was priced at $467,500.