Interested in picking up the first drop-top 911 ever? No, not one of the first, we mean THE first cabriolet 911. At RM Sotheby's upcoming Paris sale, the one-of-one 1964 Porsche 901 Cabriolet prototype will go home with a very wealthy and devoted Porsche fanatic.

Initially, Porsche's replacement for the 356 wore the 901 badge instead of the now-legendary 911 one. At the time, Peugeot claimed ownership of any car numbering with "0" in the middle, causing Porsche to swap numerals, spawning the iconic 911 badge. Still, Porsche managed to produce 82 901s for private testing and some are still making the rounds among major classic collections.

This particular 901 is significant not only for the rarity of the 901 series, but for being the sole 901 cabriolet in existence. It was created as an engineering study for an open-air 901, but when the development team decided the concept could't pass in-house testing requirements in time, the design was scrapped in favor of the Targa, which incorporated a solid roll hoop behind the driver.

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After three years in storage, the 901 Cab made its way to a Porsche collector, who kept it from 1967 until 2001, when it was traded for a Porsche 356 B Carrera GS. Myron Vernis, a well-known collector of eclectic cars, sold it to a British collector, who is the current owner.

Surprisingly, despite the glossy appearance, the 901 is in original condition, only sporting mechanical refreshes underneath the skin. Inside, there's a little more wear present, thanks to more than 50 years of use. Still, it remains in perfectly presentable condition, and is a shoo-in for prestigious concours invites around the world.