Longines has been associated as the official timekeeper for motorsports for decades, and it was this involvement that provided the inspiration for the GrandeVitesse series. Aerodynamic curves, typography and form provide distinctive features. There are three versions in the series. The Racing and Classic models feature a tachymeter, placed either on the bezel or the dial. They graduate in km/h or mph, and enable ground speed to be measured around Mach2 (twice the speed of sound or about 2,477km/h at sea level). The Racing models, which are fitted with an automatic chronograph movement, come with dials in silver sunray, black and chocolate. This model also features one pusher in bright red, which activates the chronograph functions. Classic models are available in either silver, blue, black or rhodium-plated. Both versions feature a big 12, which is taken from the form of numbers used in marking racing cars. Another model, the Cavalier, features a similar device, but it is limited to the speed of a galloping horse. The Cavalier comes with a chestnut brown dial and has Arabic numerals.