The 1913 Theta was the first production car in Europe to feature a complete electrical system as standard equipment. The first car with a monocoque body (the Lambda, produced from 1922 to 1931) also featured 'Sliding Pillar' independent front suspension that incorporated the spring and hydraulic damper into a single unit. In 1948 the first 5 speed gearbox was fitted to a production car (Series 3 Ardea). Lancia premiered the first full-production V6 engine (1950 Aurelia). It was the first company to produce a V4 engine. Lancia pioneered the use of independent suspension in production cars, in an era where live axles were common practice for both the front and rear axles of a car. They developed rear transaxles (fitted to the Aurelia and Flaminia ranges).