Files document a sports car designed by Weitz and built by Mallalieu Cars in England. The "600" is a reference to the address of Weitz's Madison Avenue office. Weitz debuted the car at Bloomingdale's and later transported it to Japan. He also designed a line of racing-inspired clothing incorporating the X600 logo. In 1981, Weitz received the Cartier Award for Design Excellence for his work on the X600. Documentation regarding the award will be found in the Awards subseries. Weitz used the car extensively in his fashion marketing; examples of clippings, proofs and tear sheets featuring the X600 will be found in the Publicity series.

Photographs depict models of the X600 photographed by John Weitz, the vehicle under construction in England, its installation in Bloomingdale's department store, and the car in various locations in New York and Japan.