"Lamborghini officially unveiled the Aventador J to the world at the 2012 Geneva Motor Show. The roofless and windowless barchetta concept car uses the same V12 engine as the standard Aventador, producing 690 hp with the same single-clutch transmission as in the standard coupé. The car does not have air conditioning or radio to save further weight for a total of 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.
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."
