Introduced in 1986, the Audemars Piguet automatic tourbillon was not only the first series produced automatic wristwatch with a tourbillon function, but is still arguably one of the world's thinnest automatic tourbillon wristwatches ever made with an overall thickness of only 4.8 mm. Perhaps the two most outstanding features that made this possible are a tourbillon cage made of titanium, dramatically reducing the weight and therefore the power required for the escapement, and the incredible innovative solution of mounting some of the jewels for pivots in the case back of the watch. Given the watch’s historical importance and the fact that it remains today unbeaten for thinness, this model will always remain a ground-breaking milestone in the chronicles of high horology.