Six months after unveiling the Aventador, plans for a roadster version were leaked by the U.S. EPA after it included the model on a data sheet on its website. Lamborghini officially unveiled the Aventador J to the world at the 2012 Geneva Motor Show.The roofless and windowless concept car uses the same V12 engine as the standard Aventador, producing 700 hp through a lightweight seven-speed automated transmission. The car does not have air conditioning or radio to save further weight for a total of 3,472 pounds (1,575 kg).The car presented at the Geneva show was the only unit to be produced, and was sold for US$2.8 million. Another Limited Edition model was made for Shaikh Al Yahyaa and was sold at an unknown price. The car was specially made for a close relation. The J designation was thought to have come from Appendix J in the FIA rulebook that describes the technical specifications of race cars.However, during an interview with designer Filippo Perini, it was revealed that the 'J' actually stands for Jota, in reference to a 1970s one off Lamborghini Miura Jota, which also conformed to the FIA's Appendix J regulations. The Aventador LP 720-4 50° Anniversario is a limited (200 units - 100 Coupe and 100 Roadster) version of the Aventador LP 700-4 commemorating the 50th anniversary of Automobili Lamborghini. It included increased engine power to 720 PS (530 kW; 710 bhp) via a new specific engine calibration, enlarged and extended front air intakes and the aerodynamic splitter, small flaps set into the sides, new rear end featuring an enlarged diffuser and expansive meshwork that further improves engine-compartment ventilation, model-exclusive Giallo Maggio (Italian for "yellow May") body colour featuring sparkling yellow paintwork with a layer of transparent and highly reflective particles; front and rear and sills in two-tone (Giallo Maggio and matte black) design, semi-aniline leather interior upholstery in Nero Ade (black) with Terra Emilia (optional Giallo Quercus (yellow)) with Q-Citura stitch diamond pattern, 50th anniversary emblem in forged composite carbon-fiber. The base price of the Aventador LP 720-4 50° is $548,000 which is $106,300 more than the Aventador Roadster.