The Triovis micro-metric adjuster from Portescap was introduced in 1968. Initially aimed at the latest high-frequency (36,000 A/h) movements, it would find widespread use in many calibres launched over the next few years. Triovis allows easy adjustment thanks to the perpendicular screw, which keeps the balance spring perfectly aligned, and the fact that the pitch of the screw thread is calibrated to 30 seconds per day per rotation.
Triovis was used by many high-end movements, including the famous F. Piguet 1180 and Lemania 5100. In modern times, it has been used in the Chopard 01 and 03, Bulgari BVL191, Girard-Perregaux GP 3100 and GP 3300, Maurice Lacroix ML76, Nomos Alpha, Ulysse Nardin Freak, and Zenith El Primero. It is also fitted to modern versions of classic movements, including the ETA 2824-2 from IWC and Tudor and ETA 7750 from Omega, Graham, Panerai, and IWC.