Silvercar, a car rental and shared mobility company, today announced its largest capital raise to date with a $28 million Series C equity issuance led by Audi. Silvercar, a rental car startup, lets users rent vehicles through an app, although it comes with one catch: The company only rents silver Audi sedans, silver Audi A4 cars—which retail starting at $35,900.

The Series C announcement comes as Silvercar unveils its enhanced digital and mobile platforms designed for an optimized user experience and expands into Las Vegas, its 12th market. Silvercar also received funding from Series B investors including Austin Ventures and Eduardo Saverin, co-founder of Facebook.

In addition to the immediate financial impact, Audi North America President Scott Keogh will be joining Silvercar’s Board of Directors. Keogh will join Ken DeAngelis, Austin Ventures, Samrat Ganguly, Velos Partners, Blair LaCorte, formerly of Texas Pacific Group, and Silvercar CEO Luke Schneider on the board.

“Audi’s confidence in Silvercar allows us to extend our reach even further, and bring forth the concept of shared mobility into many more markets, applications and product offerings,” said Silvercar CEO, Luke Schneider. “It is our goal to accelerate the expansion of our successful airport business in order to integrate these new mobility products into the market as soon as possible.”